/*-------------------------------------------------------------------------
 *
 * ruleutils.c
 *	  Functions to convert stored expressions/querytrees back to
 *	  source text
 *
 * Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  src/backend/utils/adt/ruleutils.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include <unistd.h>
#include <fcntl.h>

#ifdef PGXC
#include "access/reloptions.h"
#endif /* PGXC */
#include "access/sysattr.h"
#include "catalog/dependency.h"
#include "catalog/indexing.h"
#include "catalog/pg_authid.h"
#ifdef PGXC
#include "catalog/pg_aggregate.h"
#endif /* PGXC */
#include "catalog/pg_collation.h"
#include "catalog/pg_constraint.h"
#include "catalog/pg_depend.h"
#include "catalog/pg_language.h"
#include "catalog/pg_opclass.h"
#include "catalog/pg_operator.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_trigger.h"
#include "catalog/pg_type.h"
#include "commands/defrem.h"
#include "commands/tablespace.h"
#include "executor/spi.h"
#include "funcapi.h"
#ifdef PGXC
#include "nodes/execnodes.h"
#endif
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/clauses.h"
#include "optimizer/tlist.h"
#include "parser/keywords.h"
#include "parser/parse_func.h"
#include "parser/parse_oper.h"
#include "parser/parse_type.h"
#include "parser/parser.h"
#include "parser/parsetree.h"
#ifdef PGXC
#include "pgxc/pgxc.h"
#include "optimizer/pgxcplan.h"
#endif
#include "rewrite/rewriteHandler.h"
#include "rewrite/rewriteManip.h"
#include "rewrite/rewriteSupport.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
#include "utils/syscache.h"
#include "utils/tqual.h"
#include "utils/typcache.h"
#include "utils/xml.h"

/* ----------
 * Pretty formatting constants
 * ----------
 */

/* Indent counts */
#define PRETTYINDENT_STD		8
#define PRETTYINDENT_JOIN	   13
#define PRETTYINDENT_JOIN_ON	(PRETTYINDENT_JOIN-PRETTYINDENT_STD)
#define PRETTYINDENT_VAR		4

/* Pretty flags */
#define PRETTYFLAG_PAREN		1
#define PRETTYFLAG_INDENT		2

/* Default line length for pretty-print wrapping */
#define WRAP_COLUMN_DEFAULT		79

/* macro to test if pretty action needed */
#define PRETTY_PAREN(context)	((context)->prettyFlags & PRETTYFLAG_PAREN)
#define PRETTY_INDENT(context)	((context)->prettyFlags & PRETTYFLAG_INDENT)


/* ----------
 * Local data types
 * ----------
 */

/* Context info needed for invoking a recursive querytree display routine */
typedef struct
{
	StringInfo	buf;			/* output buffer to append to */
	List	   *namespaces;		/* List of deparse_namespace nodes */
	List	   *windowClause;	/* Current query level's WINDOW clause */
	List	   *windowTList;	/* targetlist for resolving WINDOW clause */
	int			prettyFlags;	/* enabling of pretty-print functions */
	int			wrapColumn;		/* max line length, or -1 for no limit */
	int			indentLevel;	/* current indent level for prettyprint */
	bool		varprefix;		/* TRUE to print prefixes on Vars */
#ifdef PGXC
	bool		finalise_aggs;	/* should Datanode finalise the aggregates? */
	bool		sortgroup_colno;/* instead of expression use resno for
								 * sortgrouprefs.
								 */
#endif /* PGXC */
} deparse_context;

/*
 * Each level of query context around a subtree needs a level of Var namespace.
 * A Var having varlevelsup=N refers to the N'th item (counting from 0) in
 * the current context's namespaces list.
 *
 * The rangetable is the list of actual RTEs from the query tree, and the
 * cte list is the list of actual CTEs.
 *
 * When deparsing plan trees, there is always just a single item in the
 * deparse_namespace list (since a plan tree never contains Vars with
 * varlevelsup > 0).  We store the PlanState node that is the immediate
 * parent of the expression to be deparsed, as well as a list of that
 * PlanState's ancestors.  In addition, we store its outer and inner subplan
 * state nodes, as well as their plan nodes' targetlists, and the indextlist
 * if the current PlanState is an IndexOnlyScanState.  (These fields could
 * be derived on-the-fly from the current PlanState, but it seems notationally
 * clearer to set them up as separate fields.)
 */
typedef struct
{
	List	   *rtable;			/* List of RangeTblEntry nodes */
	List	   *ctes;			/* List of CommonTableExpr nodes */
	/* Remaining fields are used only when deparsing a Plan tree: */
	PlanState  *planstate;		/* immediate parent of current expression */
	List	   *ancestors;		/* ancestors of planstate */
	PlanState  *outer_planstate;	/* outer subplan state, or NULL if none */
	PlanState  *inner_planstate;	/* inner subplan state, or NULL if none */
	List	   *outer_tlist;	/* referent for OUTER_VAR Vars */
	List	   *inner_tlist;	/* referent for INNER_VAR Vars */
	List	   *index_tlist;	/* referent for INDEX_VAR Vars */
#ifdef PGXC
	bool		remotequery;	/* deparse context for remote query */
#endif
} deparse_namespace;


/* ----------
 * Global data
 * ----------
 */
static SPIPlanPtr plan_getrulebyoid = NULL;
static const char *query_getrulebyoid = "SELECT * FROM pg_catalog.pg_rewrite WHERE oid = $1";
static SPIPlanPtr plan_getviewrule = NULL;
static const char *query_getviewrule = "SELECT * FROM pg_catalog.pg_rewrite WHERE ev_class = $1 AND rulename = $2";

/* GUC parameters */
bool		quote_all_identifiers = false;


/* ----------
 * Local functions
 *
 * Most of these functions used to use fixed-size buffers to build their
 * results.  Now, they take an (already initialized) StringInfo object
 * as a parameter, and append their text output to its contents.
 * ----------
 */
static char *deparse_expression_pretty(Node *expr, List *dpcontext,
						  bool forceprefix, bool showimplicit,
						  int prettyFlags, int startIndent);
static char *pg_get_viewdef_worker(Oid viewoid,
					  int prettyFlags, int wrapColumn);
static char *pg_get_triggerdef_worker(Oid trigid, bool pretty);
static void decompile_column_index_array(Datum column_index_array, Oid relId,
							 StringInfo buf);
static char *pg_get_ruledef_worker(Oid ruleoid, int prettyFlags);
static char *pg_get_indexdef_worker(Oid indexrelid, int colno,
					   const Oid *excludeOps,
					   bool attrsOnly, bool showTblSpc,
					   int prettyFlags);
static char *pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
							int prettyFlags);
static text *pg_get_expr_worker(text *expr, Oid relid, const char *relname,
				   int prettyFlags);
static int print_function_arguments(StringInfo buf, HeapTuple proctup,
						 bool print_table_args, bool print_defaults);
static void print_function_rettype(StringInfo buf, HeapTuple proctup);
static void set_deparse_planstate(deparse_namespace *dpns, PlanState *ps);
#ifdef PGXC
static void set_deparse_plan(deparse_namespace *dpns, Plan *plan);
#endif
static void push_child_plan(deparse_namespace *dpns, PlanState *ps,
				deparse_namespace *save_dpns);
static void pop_child_plan(deparse_namespace *dpns,
			   deparse_namespace *save_dpns);
static void push_ancestor_plan(deparse_namespace *dpns, ListCell *ancestor_cell,
				   deparse_namespace *save_dpns);
static void pop_ancestor_plan(deparse_namespace *dpns,
				  deparse_namespace *save_dpns);
static void make_ruledef(StringInfo buf, HeapTuple ruletup, TupleDesc rulettc,
			 int prettyFlags);
static void make_viewdef(StringInfo buf, HeapTuple ruletup, TupleDesc rulettc,
			 int prettyFlags, int wrapColumn);
static void get_query_def(Query *query, StringInfo buf, List *parentnamespace,
			  TupleDesc resultDesc,
			  int prettyFlags, int wrapColumn, int startIndent
#ifdef PGXC
			  , bool finalise_aggregates, bool sortgroup_colno
#endif /* PGXC */
				);
static void get_values_def(List *values_lists, deparse_context *context);
static void get_with_clause(Query *query, deparse_context *context);
static void get_select_query_def(Query *query, deparse_context *context,
					 TupleDesc resultDesc);
static void get_insert_query_def(Query *query, deparse_context *context);
static void get_update_query_def(Query *query, deparse_context *context);
static void get_delete_query_def(Query *query, deparse_context *context);
static void get_utility_query_def(Query *query, deparse_context *context);
static void get_basic_select_query(Query *query, deparse_context *context,
					   TupleDesc resultDesc);
static void get_target_list(List *targetList, deparse_context *context,
				TupleDesc resultDesc);
static void get_setop_query(Node *setOp, Query *query,
				deparse_context *context,
				TupleDesc resultDesc);
static Node *get_rule_sortgroupclause(SortGroupClause *srt, List *tlist,
						 bool force_colno,
						 deparse_context *context);
static void get_rule_orderby(List *orderList, List *targetList,
				 bool force_colno, deparse_context *context);
static void get_rule_windowclause(Query *query, deparse_context *context);
static void get_rule_windowspec(WindowClause *wc, List *targetList,
					deparse_context *context);
static char *get_variable(Var *var, int levelsup, bool istoplevel,
			 deparse_context *context);
static RangeTblEntry *find_rte_by_refname(const char *refname,
					deparse_context *context);
static Node *find_param_referent(Param *param, deparse_context *context,
					deparse_namespace **dpns_p, ListCell **ancestor_cell_p);
static void get_parameter(Param *param, deparse_context *context);
static const char *get_simple_binary_op_name(OpExpr *expr);
static bool isSimpleNode(Node *node, Node *parentNode, int prettyFlags);
static void appendContextKeyword(deparse_context *context, const char *str,
					 int indentBefore, int indentAfter, int indentPlus);
static void get_rule_expr(Node *node, deparse_context *context,
			  bool showimplicit);
static void get_oper_expr(OpExpr *expr, deparse_context *context);
static void get_func_expr(FuncExpr *expr, deparse_context *context,
			  bool showimplicit);
static void get_agg_expr(Aggref *aggref, deparse_context *context);
static void get_windowfunc_expr(WindowFunc *wfunc, deparse_context *context);
static void get_coercion_expr(Node *arg, deparse_context *context,
				  Oid resulttype, int32 resulttypmod,
				  Node *parentNode);
static void get_const_expr(Const *constval, deparse_context *context,
			   int showtype);
static void get_const_collation(Const *constval, deparse_context *context);
static void simple_quote_literal(StringInfo buf, const char *val);
static void get_sublink_expr(SubLink *sublink, deparse_context *context);
static void get_from_clause(Query *query, const char *prefix,
				deparse_context *context);
static void get_from_clause_item(Node *jtnode, Query *query,
					 deparse_context *context);
static void get_from_clause_alias(Alias *alias, RangeTblEntry *rte,
					  deparse_context *context);
static void get_from_clause_coldeflist(List *names,
						   List *types, List *typmods, List *collations,
						   deparse_context *context);
static void get_opclass_name(Oid opclass, Oid actual_datatype,
				 StringInfo buf);
static Node *processIndirection(Node *node, deparse_context *context,
				   bool printit);
static void printSubscripts(ArrayRef *aref, deparse_context *context);
static char *get_relation_name(Oid relid);
static char *generate_relation_name(Oid relid, List *namespaces);
static char *generate_function_name(Oid funcid, int nargs, List *argnames,
					   Oid *argtypes, bool *is_variadic);
static char *generate_operator_name(Oid operid, Oid arg1, Oid arg2);
static text *string_to_text(char *str);
static char *flatten_reloptions(Oid relid);

#define only_marker(rte)  ((rte)->inh ? "" : "ONLY ")


/* ----------
 * get_ruledef			- Do it all and return a text
 *				  that could be used as a statement
 *				  to recreate the rule
 * ----------
 */
Datum
pg_get_ruledef(PG_FUNCTION_ARGS)
{
	Oid			ruleoid = PG_GETARG_OID(0);

	PG_RETURN_TEXT_P(string_to_text(pg_get_ruledef_worker(ruleoid, 0)));
}


Datum
pg_get_ruledef_ext(PG_FUNCTION_ARGS)
{
	Oid			ruleoid = PG_GETARG_OID(0);
	bool		pretty = PG_GETARG_BOOL(1);
	int			prettyFlags;

	prettyFlags = pretty ? PRETTYFLAG_PAREN | PRETTYFLAG_INDENT : 0;
	PG_RETURN_TEXT_P(string_to_text(pg_get_ruledef_worker(ruleoid, prettyFlags)));
}


static char *
pg_get_ruledef_worker(Oid ruleoid, int prettyFlags)
{
	Datum		args[1];
	char		nulls[1];
	int			spirc;
	HeapTuple	ruletup;
	TupleDesc	rulettc;
	StringInfoData buf;

	/*
	 * Do this first so that string is alloc'd in outer context not SPI's.
	 */
	initStringInfo(&buf);

	/*
	 * Connect to SPI manager
	 */
	if (SPI_connect() != SPI_OK_CONNECT)
		elog(ERROR, "SPI_connect failed");

	/*
	 * On the first call prepare the plan to lookup pg_rewrite. We read
	 * pg_rewrite over the SPI manager instead of using the syscache to be
	 * checked for read access on pg_rewrite.
	 */
	if (plan_getrulebyoid == NULL)
	{
		Oid			argtypes[1];
		SPIPlanPtr	plan;

		argtypes[0] = OIDOID;
		plan = SPI_prepare(query_getrulebyoid, 1, argtypes);
		if (plan == NULL)
			elog(ERROR, "SPI_prepare failed for \"%s\"", query_getrulebyoid);
		SPI_keepplan(plan);
		plan_getrulebyoid = plan;
	}

	/*
	 * Get the pg_rewrite tuple for this rule
	 */
	args[0] = ObjectIdGetDatum(ruleoid);
	nulls[0] = ' ';
	spirc = SPI_execute_plan(plan_getrulebyoid, args, nulls, true, 1);
	if (spirc != SPI_OK_SELECT)
		elog(ERROR, "failed to get pg_rewrite tuple for rule %u", ruleoid);
	if (SPI_processed != 1)
		appendStringInfo(&buf, "-");
	else
	{
		/*
		 * Get the rule's definition and put it into executor's memory
		 */
		ruletup = SPI_tuptable->vals[0];
		rulettc = SPI_tuptable->tupdesc;
		make_ruledef(&buf, ruletup, rulettc, prettyFlags);
	}

	/*
	 * Disconnect from SPI manager
	 */
	if (SPI_finish() != SPI_OK_FINISH)
		elog(ERROR, "SPI_finish failed");

	return buf.data;
}


/* ----------
 * get_viewdef			- Mainly the same thing, but we
 *				  only return the SELECT part of a view
 * ----------
 */
Datum
pg_get_viewdef(PG_FUNCTION_ARGS)
{
	/* By OID */
	Oid			viewoid = PG_GETARG_OID(0);

	PG_RETURN_TEXT_P(string_to_text(pg_get_viewdef_worker(viewoid, 0, -1)));
}


Datum
pg_get_viewdef_ext(PG_FUNCTION_ARGS)
{
	/* By OID */
	Oid			viewoid = PG_GETARG_OID(0);
	bool		pretty = PG_GETARG_BOOL(1);
	int			prettyFlags;

	prettyFlags = pretty ? PRETTYFLAG_PAREN | PRETTYFLAG_INDENT : 0;
	PG_RETURN_TEXT_P(string_to_text(pg_get_viewdef_worker(viewoid, prettyFlags, WRAP_COLUMN_DEFAULT)));
}

Datum
pg_get_viewdef_wrap(PG_FUNCTION_ARGS)
{
	/* By OID */
	Oid			viewoid = PG_GETARG_OID(0);
	int			wrap = PG_GETARG_INT32(1);
	int			prettyFlags;
	char	   *result;

	/* calling this implies we want pretty printing */
	prettyFlags = PRETTYFLAG_PAREN | PRETTYFLAG_INDENT;
	result = pg_get_viewdef_worker(viewoid, prettyFlags, wrap);
	PG_RETURN_TEXT_P(string_to_text(result));
}

Datum
pg_get_viewdef_name(PG_FUNCTION_ARGS)
{
	/* By qualified name */
	text	   *viewname = PG_GETARG_TEXT_P(0);
	RangeVar   *viewrel;
	Oid			viewoid;

	/* Look up view name.  Can't lock it - we might not have privileges. */
	viewrel = makeRangeVarFromNameList(textToQualifiedNameList(viewname));
	viewoid = RangeVarGetRelid(viewrel, NoLock, false);

	PG_RETURN_TEXT_P(string_to_text(pg_get_viewdef_worker(viewoid, 0, -1)));
}


Datum
pg_get_viewdef_name_ext(PG_FUNCTION_ARGS)
{
	/* By qualified name */
	text	   *viewname = PG_GETARG_TEXT_P(0);
	bool		pretty = PG_GETARG_BOOL(1);
	int			prettyFlags;
	RangeVar   *viewrel;
	Oid			viewoid;

	prettyFlags = pretty ? PRETTYFLAG_PAREN | PRETTYFLAG_INDENT : 0;

	/* Look up view name.  Can't lock it - we might not have privileges. */
	viewrel = makeRangeVarFromNameList(textToQualifiedNameList(viewname));
	viewoid = RangeVarGetRelid(viewrel, NoLock, false);

	PG_RETURN_TEXT_P(string_to_text(pg_get_viewdef_worker(viewoid, prettyFlags, WRAP_COLUMN_DEFAULT)));
}

/*
 * Common code for by-OID and by-name variants of pg_get_viewdef
 */
static char *
pg_get_viewdef_worker(Oid viewoid, int prettyFlags, int wrapColumn)
{
	Datum		args[2];
	char		nulls[2];
	int			spirc;
	HeapTuple	ruletup;
	TupleDesc	rulettc;
	StringInfoData buf;

	/*
	 * Do this first so that string is alloc'd in outer context not SPI's.
	 */
	initStringInfo(&buf);

	/*
	 * Connect to SPI manager
	 */
	if (SPI_connect() != SPI_OK_CONNECT)
		elog(ERROR, "SPI_connect failed");

	/*
	 * On the first call prepare the plan to lookup pg_rewrite. We read
	 * pg_rewrite over the SPI manager instead of using the syscache to be
	 * checked for read access on pg_rewrite.
	 */
	if (plan_getviewrule == NULL)
	{
		Oid			argtypes[2];
		SPIPlanPtr	plan;

		argtypes[0] = OIDOID;
		argtypes[1] = NAMEOID;
		plan = SPI_prepare(query_getviewrule, 2, argtypes);
		if (plan == NULL)
			elog(ERROR, "SPI_prepare failed for \"%s\"", query_getviewrule);
		SPI_keepplan(plan);
		plan_getviewrule = plan;
	}

	/*
	 * Get the pg_rewrite tuple for the view's SELECT rule
	 */
	args[0] = ObjectIdGetDatum(viewoid);
	args[1] = PointerGetDatum(ViewSelectRuleName);
	nulls[0] = ' ';
	nulls[1] = ' ';
	spirc = SPI_execute_plan(plan_getviewrule, args, nulls, true, 2);
	if (spirc != SPI_OK_SELECT)
		elog(ERROR, "failed to get pg_rewrite tuple for view %u", viewoid);
	if (SPI_processed != 1)
		appendStringInfo(&buf, "Not a view");
	else
	{
		/*
		 * Get the rule's definition and put it into executor's memory
		 */
		ruletup = SPI_tuptable->vals[0];
		rulettc = SPI_tuptable->tupdesc;
		make_viewdef(&buf, ruletup, rulettc, prettyFlags, wrapColumn);
	}

	/*
	 * Disconnect from SPI manager
	 */
	if (SPI_finish() != SPI_OK_FINISH)
		elog(ERROR, "SPI_finish failed");

	return buf.data;
}

/* ----------
 * get_triggerdef			- Get the definition of a trigger
 * ----------
 */
Datum
pg_get_triggerdef(PG_FUNCTION_ARGS)
{
	Oid			trigid = PG_GETARG_OID(0);

	PG_RETURN_TEXT_P(string_to_text(pg_get_triggerdef_worker(trigid, false)));
}

Datum
pg_get_triggerdef_ext(PG_FUNCTION_ARGS)
{
	Oid			trigid = PG_GETARG_OID(0);
	bool		pretty = PG_GETARG_BOOL(1);

	PG_RETURN_TEXT_P(string_to_text(pg_get_triggerdef_worker(trigid, pretty)));
}

static char *
pg_get_triggerdef_worker(Oid trigid, bool pretty)
{
	HeapTuple	ht_trig;
	Form_pg_trigger trigrec;
	StringInfoData buf;
	Relation	tgrel;
	ScanKeyData skey[1];
	SysScanDesc tgscan;
	int			findx = 0;
	char	   *tgname;
	Datum		value;
	bool		isnull;

	/*
	 * Fetch the pg_trigger tuple by the Oid of the trigger
	 */
	tgrel = heap_open(TriggerRelationId, AccessShareLock);

	ScanKeyInit(&skey[0],
				ObjectIdAttributeNumber,
				BTEqualStrategyNumber, F_OIDEQ,
				ObjectIdGetDatum(trigid));

	tgscan = systable_beginscan(tgrel, TriggerOidIndexId, true,
								SnapshotNow, 1, skey);

	ht_trig = systable_getnext(tgscan);

	if (!HeapTupleIsValid(ht_trig))
		elog(ERROR, "could not find tuple for trigger %u", trigid);

	trigrec = (Form_pg_trigger) GETSTRUCT(ht_trig);

	/*
	 * Start the trigger definition. Note that the trigger's name should never
	 * be schema-qualified, but the trigger rel's name may be.
	 */
	initStringInfo(&buf);

	tgname = NameStr(trigrec->tgname);
	appendStringInfo(&buf, "CREATE %sTRIGGER %s ",
					 OidIsValid(trigrec->tgconstraint) ? "CONSTRAINT " : "",
					 quote_identifier(tgname));

	if (TRIGGER_FOR_BEFORE(trigrec->tgtype))
		appendStringInfo(&buf, "BEFORE");
	else if (TRIGGER_FOR_AFTER(trigrec->tgtype))
		appendStringInfo(&buf, "AFTER");
	else if (TRIGGER_FOR_INSTEAD(trigrec->tgtype))
		appendStringInfo(&buf, "INSTEAD OF");
	else
		elog(ERROR, "unexpected tgtype value: %d", trigrec->tgtype);

	if (TRIGGER_FOR_INSERT(trigrec->tgtype))
	{
		appendStringInfo(&buf, " INSERT");
		findx++;
	}
	if (TRIGGER_FOR_DELETE(trigrec->tgtype))
	{
		if (findx > 0)
			appendStringInfo(&buf, " OR DELETE");
		else
			appendStringInfo(&buf, " DELETE");
		findx++;
	}
	if (TRIGGER_FOR_UPDATE(trigrec->tgtype))
	{
		if (findx > 0)
			appendStringInfo(&buf, " OR UPDATE");
		else
			appendStringInfo(&buf, " UPDATE");
		findx++;
		/* tgattr is first var-width field, so OK to access directly */
		if (trigrec->tgattr.dim1 > 0)
		{
			int			i;

			appendStringInfoString(&buf, " OF ");
			for (i = 0; i < trigrec->tgattr.dim1; i++)
			{
				char	   *attname;

				if (i > 0)
					appendStringInfoString(&buf, ", ");
				attname = get_relid_attribute_name(trigrec->tgrelid,
												   trigrec->tgattr.values[i]);
				appendStringInfoString(&buf, quote_identifier(attname));
			}
		}
	}
	if (TRIGGER_FOR_TRUNCATE(trigrec->tgtype))
	{
		if (findx > 0)
			appendStringInfo(&buf, " OR TRUNCATE");
		else
			appendStringInfo(&buf, " TRUNCATE");
		findx++;
	}
	appendStringInfo(&buf, " ON %s ",
					 generate_relation_name(trigrec->tgrelid, NIL));

	if (OidIsValid(trigrec->tgconstraint))
	{
		if (OidIsValid(trigrec->tgconstrrelid))
			appendStringInfo(&buf, "FROM %s ",
						generate_relation_name(trigrec->tgconstrrelid, NIL));
		if (!trigrec->tgdeferrable)
			appendStringInfo(&buf, "NOT ");
		appendStringInfo(&buf, "DEFERRABLE INITIALLY ");
		if (trigrec->tginitdeferred)
			appendStringInfo(&buf, "DEFERRED ");
		else
			appendStringInfo(&buf, "IMMEDIATE ");
	}

	if (TRIGGER_FOR_ROW(trigrec->tgtype))
		appendStringInfo(&buf, "FOR EACH ROW ");
	else
		appendStringInfo(&buf, "FOR EACH STATEMENT ");

	/* If the trigger has a WHEN qualification, add that */
	value = fastgetattr(ht_trig, Anum_pg_trigger_tgqual,
						tgrel->rd_att, &isnull);
	if (!isnull)
	{
		Node	   *qual;
		char		relkind;
		deparse_context context;
		deparse_namespace dpns;
		RangeTblEntry *oldrte;
		RangeTblEntry *newrte;

		appendStringInfoString(&buf, "WHEN (");

		qual = stringToNode(TextDatumGetCString(value));

		relkind = get_rel_relkind(trigrec->tgrelid);

		/* Build minimal OLD and NEW RTEs for the rel */
		oldrte = makeNode(RangeTblEntry);
		oldrte->rtekind = RTE_RELATION;
		oldrte->relid = trigrec->tgrelid;
		oldrte->relkind = relkind;
		oldrte->eref = makeAlias("old", NIL);
		oldrte->inh = false;
		oldrte->inFromCl = true;

		newrte = makeNode(RangeTblEntry);
		newrte->rtekind = RTE_RELATION;
		newrte->relid = trigrec->tgrelid;
		newrte->relkind = relkind;
		newrte->eref = makeAlias("new", NIL);
		newrte->inh = false;
		newrte->inFromCl = true;

		/* Build two-element rtable */
		memset(&dpns, 0, sizeof(dpns));
		dpns.rtable = list_make2(oldrte, newrte);
		dpns.ctes = NIL;

		/* Set up context with one-deep namespace stack */
		context.buf = &buf;
		context.namespaces = list_make1(&dpns);
		context.windowClause = NIL;
		context.windowTList = NIL;
		context.varprefix = true;
		context.prettyFlags = pretty ? PRETTYFLAG_PAREN : 0;
#ifdef PGXC
		context.finalise_aggs = false;
#endif /* PGXC */
		context.wrapColumn = WRAP_COLUMN_DEFAULT;
		context.indentLevel = PRETTYINDENT_STD;

		get_rule_expr(qual, &context, false);

		appendStringInfo(&buf, ") ");
	}

	appendStringInfo(&buf, "EXECUTE PROCEDURE %s(",
					 generate_function_name(trigrec->tgfoid, 0,
											NIL, NULL, NULL));

	if (trigrec->tgnargs > 0)
	{
		char	   *p;
		int			i;

		value = fastgetattr(ht_trig, Anum_pg_trigger_tgargs,
							tgrel->rd_att, &isnull);
		if (isnull)
			elog(ERROR, "tgargs is null for trigger %u", trigid);
		p = (char *) VARDATA(DatumGetByteaP(value));
		for (i = 0; i < trigrec->tgnargs; i++)
		{
			if (i > 0)
				appendStringInfo(&buf, ", ");
			simple_quote_literal(&buf, p);
			/* advance p to next string embedded in tgargs */
			while (*p)
				p++;
			p++;
		}
	}

	/* We deliberately do not put semi-colon at end */
	appendStringInfo(&buf, ")");

	/* Clean up */
	systable_endscan(tgscan);

	heap_close(tgrel, AccessShareLock);

	return buf.data;
}

/* ----------
 * get_indexdef			- Get the definition of an index
 *
 * In the extended version, there is a colno argument as well as pretty bool.
 *	if colno == 0, we want a complete index definition.
 *	if colno > 0, we only want the Nth index key's variable or expression.
 *
 * Note that the SQL-function versions of this omit any info about the
 * index tablespace; this is intentional because pg_dump wants it that way.
 * However pg_get_indexdef_string() includes index tablespace if not default.
 * ----------
 */
Datum
pg_get_indexdef(PG_FUNCTION_ARGS)
{
	Oid			indexrelid = PG_GETARG_OID(0);

	PG_RETURN_TEXT_P(string_to_text(pg_get_indexdef_worker(indexrelid, 0,
														   NULL,
														   false, false, 0)));
}

Datum
pg_get_indexdef_ext(PG_FUNCTION_ARGS)
{
	Oid			indexrelid = PG_GETARG_OID(0);
	int32		colno = PG_GETARG_INT32(1);
	bool		pretty = PG_GETARG_BOOL(2);
	int			prettyFlags;

	prettyFlags = pretty ? PRETTYFLAG_PAREN | PRETTYFLAG_INDENT : 0;
	PG_RETURN_TEXT_P(string_to_text(pg_get_indexdef_worker(indexrelid, colno,
														   NULL,
														   colno != 0,
														   false,
														   prettyFlags)));
}

/* Internal version that returns a palloc'd C string */
char *
pg_get_indexdef_string(Oid indexrelid)
{
	return pg_get_indexdef_worker(indexrelid, 0, NULL, false, true, 0);
}

/* Internal version that just reports the column definitions */
char *
pg_get_indexdef_columns(Oid indexrelid, bool pretty)
{
	int			prettyFlags;

	prettyFlags = pretty ? PRETTYFLAG_PAREN | PRETTYFLAG_INDENT : 0;
	return pg_get_indexdef_worker(indexrelid, 0, NULL, true, false, prettyFlags);
}

/*
 * Internal workhorse to decompile an index definition.
 *
 * This is now used for exclusion constraints as well: if excludeOps is not
 * NULL then it points to an array of exclusion operator OIDs.
 */
static char *
pg_get_indexdef_worker(Oid indexrelid, int colno,
					   const Oid *excludeOps,
					   bool attrsOnly, bool showTblSpc,
					   int prettyFlags)
{
	/* might want a separate isConstraint parameter later */
	bool		isConstraint = (excludeOps != NULL);
	HeapTuple	ht_idx;
	HeapTuple	ht_idxrel;
	HeapTuple	ht_am;
	Form_pg_index idxrec;
	Form_pg_class idxrelrec;
	Form_pg_am	amrec;
	List	   *indexprs;
	ListCell   *indexpr_item;
	List	   *context;
	Oid			indrelid;
	int			keyno;
	Datum		indcollDatum;
	Datum		indclassDatum;
	Datum		indoptionDatum;
	bool		isnull;
	oidvector  *indcollation;
	oidvector  *indclass;
	int2vector *indoption;
	StringInfoData buf;
	char	   *str;
	char	   *sep;

	/*
	 * Fetch the pg_index tuple by the Oid of the index
	 */
	ht_idx = SearchSysCache1(INDEXRELID, ObjectIdGetDatum(indexrelid));
	if (!HeapTupleIsValid(ht_idx))
		elog(ERROR, "cache lookup failed for index %u", indexrelid);
	idxrec = (Form_pg_index) GETSTRUCT(ht_idx);

	indrelid = idxrec->indrelid;
	Assert(indexrelid == idxrec->indexrelid);

	/* Must get indcollation, indclass, and indoption the hard way */
	indcollDatum = SysCacheGetAttr(INDEXRELID, ht_idx,
								   Anum_pg_index_indcollation, &isnull);
	Assert(!isnull);
	indcollation = (oidvector *) DatumGetPointer(indcollDatum);

	indclassDatum = SysCacheGetAttr(INDEXRELID, ht_idx,
									Anum_pg_index_indclass, &isnull);
	Assert(!isnull);
	indclass = (oidvector *) DatumGetPointer(indclassDatum);

	indoptionDatum = SysCacheGetAttr(INDEXRELID, ht_idx,
									 Anum_pg_index_indoption, &isnull);
	Assert(!isnull);
	indoption = (int2vector *) DatumGetPointer(indoptionDatum);

	/*
	 * Fetch the pg_class tuple of the index relation
	 */
	ht_idxrel = SearchSysCache1(RELOID, ObjectIdGetDatum(indexrelid));
	if (!HeapTupleIsValid(ht_idxrel))
		elog(ERROR, "cache lookup failed for relation %u", indexrelid);
	idxrelrec = (Form_pg_class) GETSTRUCT(ht_idxrel);

	/*
	 * Fetch the pg_am tuple of the index' access method
	 */
	ht_am = SearchSysCache1(AMOID, ObjectIdGetDatum(idxrelrec->relam));
	if (!HeapTupleIsValid(ht_am))
		elog(ERROR, "cache lookup failed for access method %u",
			 idxrelrec->relam);
	amrec = (Form_pg_am) GETSTRUCT(ht_am);

	/*
	 * Get the index expressions, if any.  (NOTE: we do not use the relcache
	 * versions of the expressions and predicate, because we want to display
	 * non-const-folded expressions.)
	 */
	if (!heap_attisnull(ht_idx, Anum_pg_index_indexprs))
	{
		Datum		exprsDatum;
		bool		isnull;
		char	   *exprsString;

		exprsDatum = SysCacheGetAttr(INDEXRELID, ht_idx,
									 Anum_pg_index_indexprs, &isnull);
		Assert(!isnull);
		exprsString = TextDatumGetCString(exprsDatum);
		indexprs = (List *) stringToNode(exprsString);
		pfree(exprsString);
	}
	else
		indexprs = NIL;

	indexpr_item = list_head(indexprs);

	context = deparse_context_for(get_relation_name(indrelid), indrelid);

	/*
	 * Start the index definition.	Note that the index's name should never be
	 * schema-qualified, but the indexed rel's name may be.
	 */
	initStringInfo(&buf);

	if (!attrsOnly)
	{
		if (!isConstraint)
			appendStringInfo(&buf, "CREATE %sINDEX %s ON %s USING %s (",
							 idxrec->indisunique ? "UNIQUE " : "",
							 quote_identifier(NameStr(idxrelrec->relname)),
							 generate_relation_name(indrelid, NIL),
							 quote_identifier(NameStr(amrec->amname)));
		else	/* currently, must be EXCLUDE constraint */
			appendStringInfo(&buf, "EXCLUDE USING %s (",
							 quote_identifier(NameStr(amrec->amname)));
	}

	/*
	 * Report the indexed attributes
	 */
	sep = "";
	for (keyno = 0; keyno < idxrec->indnatts; keyno++)
	{
		AttrNumber	attnum = idxrec->indkey.values[keyno];
		int16		opt = indoption->values[keyno];
		Oid			keycoltype;
		Oid			keycolcollation;

		if (!colno)
			appendStringInfoString(&buf, sep);
		sep = ", ";

		if (attnum != 0)
		{
			/* Simple index column */
			char	   *attname;
			int32		keycoltypmod;

			attname = get_relid_attribute_name(indrelid, attnum);
			if (!colno || colno == keyno + 1)
				appendStringInfoString(&buf, quote_identifier(attname));
			get_atttypetypmodcoll(indrelid, attnum,
								  &keycoltype, &keycoltypmod,
								  &keycolcollation);
		}
		else
		{
			/* expressional index */
			Node	   *indexkey;

			if (indexpr_item == NULL)
				elog(ERROR, "too few entries in indexprs list");
			indexkey = (Node *) lfirst(indexpr_item);
			indexpr_item = lnext(indexpr_item);
			/* Deparse */
			str = deparse_expression_pretty(indexkey, context, false, false,
											prettyFlags, 0);
			if (!colno || colno == keyno + 1)
			{
				/* Need parens if it's not a bare function call */
				if (indexkey && IsA(indexkey, FuncExpr) &&
				 ((FuncExpr *) indexkey)->funcformat == COERCE_EXPLICIT_CALL)
					appendStringInfoString(&buf, str);
				else
					appendStringInfo(&buf, "(%s)", str);
			}
			keycoltype = exprType(indexkey);
			keycolcollation = exprCollation(indexkey);
		}

		if (!attrsOnly && (!colno || colno == keyno + 1))
		{
			Oid			indcoll;

			/* Add collation, if not default for column */
			indcoll = indcollation->values[keyno];
			if (OidIsValid(indcoll) && indcoll != keycolcollation)
				appendStringInfo(&buf, " COLLATE %s",
								 generate_collation_name((indcoll)));

			/* Add the operator class name, if not default */
			get_opclass_name(indclass->values[keyno], keycoltype, &buf);

			/* Add options if relevant */
			if (amrec->amcanorder)
			{
				/* if it supports sort ordering, report DESC and NULLS opts */
				if (opt & INDOPTION_DESC)
				{
					appendStringInfo(&buf, " DESC");
					/* NULLS FIRST is the default in this case */
					if (!(opt & INDOPTION_NULLS_FIRST))
						appendStringInfo(&buf, " NULLS LAST");
				}
				else
				{
					if (opt & INDOPTION_NULLS_FIRST)
						appendStringInfo(&buf, " NULLS FIRST");
				}
			}

			/* Add the exclusion operator if relevant */
			if (excludeOps != NULL)
				appendStringInfo(&buf, " WITH %s",
								 generate_operator_name(excludeOps[keyno],
														keycoltype,
														keycoltype));
		}
	}

	if (!attrsOnly)
	{
		appendStringInfoChar(&buf, ')');

		/*
		 * If it has options, append "WITH (options)"
		 */
		str = flatten_reloptions(indexrelid);
		if (str)
		{
			appendStringInfo(&buf, " WITH (%s)", str);
			pfree(str);
		}

		/*
		 * If it's in a nondefault tablespace, say so, but only if requested
		 */
		if (showTblSpc)
		{
			Oid			tblspc;

			tblspc = get_rel_tablespace(indexrelid);
			if (OidIsValid(tblspc))
			{
				if (isConstraint)
					appendStringInfoString(&buf, " USING INDEX");
				appendStringInfo(&buf, " TABLESPACE %s",
							  quote_identifier(get_tablespace_name(tblspc)));
			}
		}

		/*
		 * If it's a partial index, decompile and append the predicate
		 */
		if (!heap_attisnull(ht_idx, Anum_pg_index_indpred))
		{
			Node	   *node;
			Datum		predDatum;
			bool		isnull;
			char	   *predString;

			/* Convert text string to node tree */
			predDatum = SysCacheGetAttr(INDEXRELID, ht_idx,
										Anum_pg_index_indpred, &isnull);
			Assert(!isnull);
			predString = TextDatumGetCString(predDatum);
			node = (Node *) stringToNode(predString);
			pfree(predString);

			/* Deparse */
			str = deparse_expression_pretty(node, context, false, false,
											prettyFlags, 0);
			if (isConstraint)
				appendStringInfo(&buf, " WHERE (%s)", str);
			else
				appendStringInfo(&buf, " WHERE %s", str);
		}
	}

	/* Clean up */
	ReleaseSysCache(ht_idx);
	ReleaseSysCache(ht_idxrel);
	ReleaseSysCache(ht_am);

	return buf.data;
}


/*
 * pg_get_constraintdef
 *
 * Returns the definition for the constraint, ie, everything that needs to
 * appear after "ALTER TABLE ... ADD CONSTRAINT <constraintname>".
 */
Datum
pg_get_constraintdef(PG_FUNCTION_ARGS)
{
	Oid			constraintId = PG_GETARG_OID(0);

	PG_RETURN_TEXT_P(string_to_text(pg_get_constraintdef_worker(constraintId,
																false, 0)));
}

Datum
pg_get_constraintdef_ext(PG_FUNCTION_ARGS)
{
	Oid			constraintId = PG_GETARG_OID(0);
	bool		pretty = PG_GETARG_BOOL(1);
	int			prettyFlags;

	prettyFlags = pretty ? PRETTYFLAG_PAREN | PRETTYFLAG_INDENT : 0;
	PG_RETURN_TEXT_P(string_to_text(pg_get_constraintdef_worker(constraintId,
													   false, prettyFlags)));
}

/* Internal version that returns a palloc'd C string */
char *
pg_get_constraintdef_string(Oid constraintId)
{
	return pg_get_constraintdef_worker(constraintId, true, 0);
}

static char *
pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
							int prettyFlags)
{
	HeapTuple	tup;
	Form_pg_constraint conForm;
	StringInfoData buf;

	tup = SearchSysCache1(CONSTROID, ObjectIdGetDatum(constraintId));
	if (!HeapTupleIsValid(tup)) /* should not happen */
		elog(ERROR, "cache lookup failed for constraint %u", constraintId);
	conForm = (Form_pg_constraint) GETSTRUCT(tup);

	initStringInfo(&buf);

	if (fullCommand && OidIsValid(conForm->conrelid))
	{
		appendStringInfo(&buf, "ALTER TABLE ONLY %s ADD CONSTRAINT %s ",
						 generate_relation_name(conForm->conrelid, NIL),
						 quote_identifier(NameStr(conForm->conname)));
	}

	switch (conForm->contype)
	{
		case CONSTRAINT_FOREIGN:
			{
				Datum		val;
				bool		isnull;
				const char *string;

				/* Start off the constraint definition */
				appendStringInfo(&buf, "FOREIGN KEY (");

				/* Fetch and build referencing-column list */
				val = SysCacheGetAttr(CONSTROID, tup,
									  Anum_pg_constraint_conkey, &isnull);
				if (isnull)
					elog(ERROR, "null conkey for constraint %u",
						 constraintId);

				decompile_column_index_array(val, conForm->conrelid, &buf);

				/* add foreign relation name */
				appendStringInfo(&buf, ") REFERENCES %s(",
								 generate_relation_name(conForm->confrelid,
														NIL));

				/* Fetch and build referenced-column list */
				val = SysCacheGetAttr(CONSTROID, tup,
									  Anum_pg_constraint_confkey, &isnull);
				if (isnull)
					elog(ERROR, "null confkey for constraint %u",
						 constraintId);

				decompile_column_index_array(val, conForm->confrelid, &buf);

				appendStringInfo(&buf, ")");

				/* Add match type */
				switch (conForm->confmatchtype)
				{
					case FKCONSTR_MATCH_FULL:
						string = " MATCH FULL";
						break;
					case FKCONSTR_MATCH_PARTIAL:
						string = " MATCH PARTIAL";
						break;
					case FKCONSTR_MATCH_UNSPECIFIED:
						string = "";
						break;
					default:
						elog(ERROR, "unrecognized confmatchtype: %d",
							 conForm->confmatchtype);
						string = "";	/* keep compiler quiet */
						break;
				}
				appendStringInfoString(&buf, string);

				/* Add ON UPDATE and ON DELETE clauses, if needed */
				switch (conForm->confupdtype)
				{
					case FKCONSTR_ACTION_NOACTION:
						string = NULL;	/* suppress default */
						break;
					case FKCONSTR_ACTION_RESTRICT:
						string = "RESTRICT";
						break;
					case FKCONSTR_ACTION_CASCADE:
						string = "CASCADE";
						break;
					case FKCONSTR_ACTION_SETNULL:
						string = "SET NULL";
						break;
					case FKCONSTR_ACTION_SETDEFAULT:
						string = "SET DEFAULT";
						break;
					default:
						elog(ERROR, "unrecognized confupdtype: %d",
							 conForm->confupdtype);
						string = NULL;	/* keep compiler quiet */
						break;
				}
				if (string)
					appendStringInfo(&buf, " ON UPDATE %s", string);

				switch (conForm->confdeltype)
				{
					case FKCONSTR_ACTION_NOACTION:
						string = NULL;	/* suppress default */
						break;
					case FKCONSTR_ACTION_RESTRICT:
						string = "RESTRICT";
						break;
					case FKCONSTR_ACTION_CASCADE:
						string = "CASCADE";
						break;
					case FKCONSTR_ACTION_SETNULL:
						string = "SET NULL";
						break;
					case FKCONSTR_ACTION_SETDEFAULT:
						string = "SET DEFAULT";
						break;
					default:
						elog(ERROR, "unrecognized confdeltype: %d",
							 conForm->confdeltype);
						string = NULL;	/* keep compiler quiet */
						break;
				}
				if (string)
					appendStringInfo(&buf, " ON DELETE %s", string);

				break;
			}
		case CONSTRAINT_PRIMARY:
		case CONSTRAINT_UNIQUE:
			{
				Datum		val;
				bool		isnull;
				Oid			indexId;

				/* Start off the constraint definition */
				if (conForm->contype == CONSTRAINT_PRIMARY)
					appendStringInfo(&buf, "PRIMARY KEY (");
				else
					appendStringInfo(&buf, "UNIQUE (");

				/* Fetch and build target column list */
				val = SysCacheGetAttr(CONSTROID, tup,
									  Anum_pg_constraint_conkey, &isnull);
				if (isnull)
					elog(ERROR, "null conkey for constraint %u",
						 constraintId);

				decompile_column_index_array(val, conForm->conrelid, &buf);

				appendStringInfo(&buf, ")");

				indexId = get_constraint_index(constraintId);

				/* XXX why do we only print these bits if fullCommand? */
				if (fullCommand && OidIsValid(indexId))
				{
					char	   *options = flatten_reloptions(indexId);
					Oid			tblspc;

					if (options)
					{
						appendStringInfo(&buf, " WITH (%s)", options);
						pfree(options);
					}

					tblspc = get_rel_tablespace(indexId);
					if (OidIsValid(tblspc))
						appendStringInfo(&buf, " USING INDEX TABLESPACE %s",
							  quote_identifier(get_tablespace_name(tblspc)));
				}

				break;
			}
		case CONSTRAINT_CHECK:
			{
				Datum		val;
				bool		isnull;
				char	   *conbin;
				char	   *consrc;
				Node	   *expr;
				List	   *context;

				/* Fetch constraint expression in parsetree form */
				val = SysCacheGetAttr(CONSTROID, tup,
									  Anum_pg_constraint_conbin, &isnull);
				if (isnull)
					elog(ERROR, "null conbin for constraint %u",
						 constraintId);

				conbin = TextDatumGetCString(val);
				expr = stringToNode(conbin);

				/* Set up deparsing context for Var nodes in constraint */
				if (conForm->conrelid != InvalidOid)
				{
					/* relation constraint */
					context = deparse_context_for(get_relation_name(conForm->conrelid),
												  conForm->conrelid);
				}
				else
				{
					/* domain constraint --- can't have Vars */
					context = NIL;
				}

				consrc = deparse_expression_pretty(expr, context, false, false,
												   prettyFlags, 0);

				/*
				 * Now emit the constraint definition, adding NO INHERIT if
				 * necessary.
				 *
				 * There are cases where the constraint expression will be
				 * fully parenthesized and we don't need the outer parens ...
				 * but there are other cases where we do need 'em.  Be
				 * conservative for now.
				 *
				 * Note that simply checking for leading '(' and trailing ')'
				 * would NOT be good enough, consider "(x > 0) AND (y > 0)".
				 */
				appendStringInfo(&buf, "CHECK (%s)%s",
								 consrc,
								 conForm->connoinherit ? " NO INHERIT" : "");
				break;
			}
		case CONSTRAINT_TRIGGER:

			/*
			 * There isn't an ALTER TABLE syntax for creating a user-defined
			 * constraint trigger, but it seems better to print something than
			 * throw an error; if we throw error then this function couldn't
			 * safely be applied to all rows of pg_constraint.
			 */
			appendStringInfo(&buf, "TRIGGER");
			break;
		case CONSTRAINT_EXCLUSION:
			{
				Oid			indexOid = conForm->conindid;
				Datum		val;
				bool		isnull;
				Datum	   *elems;
				int			nElems;
				int			i;
				Oid		   *operators;

				/* Extract operator OIDs from the pg_constraint tuple */
				val = SysCacheGetAttr(CONSTROID, tup,
									  Anum_pg_constraint_conexclop,
									  &isnull);
				if (isnull)
					elog(ERROR, "null conexclop for constraint %u",
						 constraintId);

				deconstruct_array(DatumGetArrayTypeP(val),
								  OIDOID, sizeof(Oid), true, 'i',
								  &elems, NULL, &nElems);

				operators = (Oid *) palloc(nElems * sizeof(Oid));
				for (i = 0; i < nElems; i++)
					operators[i] = DatumGetObjectId(elems[i]);

				/* pg_get_indexdef_worker does the rest */
				/* suppress tablespace because pg_dump wants it that way */
				appendStringInfoString(&buf,
									   pg_get_indexdef_worker(indexOid,
															  0,
															  operators,
															  false,
															  false,
															  prettyFlags));
				break;
			}
		default:
			elog(ERROR, "invalid constraint type \"%c\"", conForm->contype);
			break;
	}

	if (conForm->condeferrable)
		appendStringInfo(&buf, " DEFERRABLE");
	if (conForm->condeferred)
		appendStringInfo(&buf, " INITIALLY DEFERRED");
	if (!conForm->convalidated)
		appendStringInfoString(&buf, " NOT VALID");

	/* Cleanup */
	ReleaseSysCache(tup);

	return buf.data;
}


/*
 * Convert an int16[] Datum into a comma-separated list of column names
 * for the indicated relation; append the list to buf.
 */
static void
decompile_column_index_array(Datum column_index_array, Oid relId,
							 StringInfo buf)
{
	Datum	   *keys;
	int			nKeys;
	int			j;

	/* Extract data from array of int16 */
	deconstruct_array(DatumGetArrayTypeP(column_index_array),
					  INT2OID, 2, true, 's',
					  &keys, NULL, &nKeys);

	for (j = 0; j < nKeys; j++)
	{
		char	   *colName;

		colName = get_relid_attribute_name(relId, DatumGetInt16(keys[j]));

		if (j == 0)
			appendStringInfoString(buf, quote_identifier(colName));
		else
			appendStringInfo(buf, ", %s", quote_identifier(colName));
	}
}


/* ----------
 * get_expr			- Decompile an expression tree
 *
 * Input: an expression tree in nodeToString form, and a relation OID
 *
 * Output: reverse-listed expression
 *
 * Currently, the expression can only refer to a single relation, namely
 * the one specified by the second parameter.  This is sufficient for
 * partial indexes, column default expressions, etc.  We also support
 * Var-free expressions, for which the OID can be InvalidOid.
 * ----------
 */
Datum
pg_get_expr(PG_FUNCTION_ARGS)
{
	text	   *expr = PG_GETARG_TEXT_P(0);
	Oid			relid = PG_GETARG_OID(1);
	char	   *relname;

	if (OidIsValid(relid))
	{
		/* Get the name for the relation */
		relname = get_rel_name(relid);

		/*
		 * If the OID isn't actually valid, don't throw an error, just return
		 * NULL.  This is a bit questionable, but it's what we've done
		 * historically, and it can help avoid unwanted failures when
		 * examining catalog entries for just-deleted relations.
		 */
		if (relname == NULL)
			PG_RETURN_NULL();
	}
	else
		relname = NULL;

	PG_RETURN_TEXT_P(pg_get_expr_worker(expr, relid, relname, 0));
}

Datum
pg_get_expr_ext(PG_FUNCTION_ARGS)
{
	text	   *expr = PG_GETARG_TEXT_P(0);
	Oid			relid = PG_GETARG_OID(1);
	bool		pretty = PG_GETARG_BOOL(2);
	int			prettyFlags;
	char	   *relname;

	prettyFlags = pretty ? PRETTYFLAG_PAREN | PRETTYFLAG_INDENT : 0;

	if (OidIsValid(relid))
	{
		/* Get the name for the relation */
		relname = get_rel_name(relid);
		/* See notes above */
		if (relname == NULL)
			PG_RETURN_NULL();
	}
	else
		relname = NULL;

	PG_RETURN_TEXT_P(pg_get_expr_worker(expr, relid, relname, prettyFlags));
}

static text *
pg_get_expr_worker(text *expr, Oid relid, const char *relname, int prettyFlags)
{
	Node	   *node;
	List	   *context;
	char	   *exprstr;
	char	   *str;

	/* Convert input TEXT object to C string */
	exprstr = text_to_cstring(expr);

	/* Convert expression to node tree */
	node = (Node *) stringToNode(exprstr);

	pfree(exprstr);

	/* Prepare deparse context if needed */
	if (OidIsValid(relid))
		context = deparse_context_for(relname, relid);
	else
		context = NIL;

	/* Deparse */
	str = deparse_expression_pretty(node, context, false, false,
									prettyFlags, 0);

	return string_to_text(str);
}


/* ----------
 * get_userbyid			- Get a user name by roleid and
 *				  fallback to 'unknown (OID=n)'
 * ----------
 */
Datum
pg_get_userbyid(PG_FUNCTION_ARGS)
{
	Oid			roleid = PG_GETARG_OID(0);
	Name		result;
	HeapTuple	roletup;
	Form_pg_authid role_rec;

	/*
	 * Allocate space for the result
	 */
	result = (Name) palloc(NAMEDATALEN);
	memset(NameStr(*result), 0, NAMEDATALEN);

	/*
	 * Get the pg_authid entry and print the result
	 */
	roletup = SearchSysCache1(AUTHOID, ObjectIdGetDatum(roleid));
	if (HeapTupleIsValid(roletup))
	{
		role_rec = (Form_pg_authid) GETSTRUCT(roletup);
		StrNCpy(NameStr(*result), NameStr(role_rec->rolname), NAMEDATALEN);
		ReleaseSysCache(roletup);
	}
	else
		sprintf(NameStr(*result), "unknown (OID=%u)", roleid);

	PG_RETURN_NAME(result);
}


/*
 * pg_get_serial_sequence
 *		Get the name of the sequence used by a serial column,
 *		formatted suitably for passing to setval, nextval or currval.
 *		First parameter is not treated as double-quoted, second parameter
 *		is --- see documentation for reason.
 */
Datum
pg_get_serial_sequence(PG_FUNCTION_ARGS)
{
	text	   *tablename = PG_GETARG_TEXT_P(0);
	text	   *columnname = PG_GETARG_TEXT_PP(1);
	RangeVar   *tablerv;
	Oid			tableOid;
	char	   *column;
	AttrNumber	attnum;
	Oid			sequenceId = InvalidOid;
	Relation	depRel;
	ScanKeyData key[3];
	SysScanDesc scan;
	HeapTuple	tup;

	/* Look up table name.	Can't lock it - we might not have privileges. */
	tablerv = makeRangeVarFromNameList(textToQualifiedNameList(tablename));
	tableOid = RangeVarGetRelid(tablerv, NoLock, false);

	/* Get the number of the column */
	column = text_to_cstring(columnname);

	attnum = get_attnum(tableOid, column);
	if (attnum == InvalidAttrNumber)
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_COLUMN),
				 errmsg("column \"%s\" of relation \"%s\" does not exist",
						column, tablerv->relname)));

	/* Search the dependency table for the dependent sequence */
	depRel = heap_open(DependRelationId, AccessShareLock);

	ScanKeyInit(&key[0],
				Anum_pg_depend_refclassid,
				BTEqualStrategyNumber, F_OIDEQ,
				ObjectIdGetDatum(RelationRelationId));
	ScanKeyInit(&key[1],
				Anum_pg_depend_refobjid,
				BTEqualStrategyNumber, F_OIDEQ,
				ObjectIdGetDatum(tableOid));
	ScanKeyInit(&key[2],
				Anum_pg_depend_refobjsubid,
				BTEqualStrategyNumber, F_INT4EQ,
				Int32GetDatum(attnum));

	scan = systable_beginscan(depRel, DependReferenceIndexId, true,
							  SnapshotNow, 3, key);

	while (HeapTupleIsValid(tup = systable_getnext(scan)))
	{
		Form_pg_depend deprec = (Form_pg_depend) GETSTRUCT(tup);

		/*
		 * We assume any auto dependency of a sequence on a column must be
		 * what we are looking for.  (We need the relkind test because indexes
		 * can also have auto dependencies on columns.)
		 */
		if (deprec->classid == RelationRelationId &&
			deprec->objsubid == 0 &&
			deprec->deptype == DEPENDENCY_AUTO &&
			get_rel_relkind(deprec->objid) == RELKIND_SEQUENCE)
		{
			sequenceId = deprec->objid;
			break;
		}
	}

	systable_endscan(scan);
	heap_close(depRel, AccessShareLock);

	if (OidIsValid(sequenceId))
	{
		HeapTuple	classtup;
		Form_pg_class classtuple;
		char	   *nspname;
		char	   *result;

		/* Get the sequence's pg_class entry */
		classtup = SearchSysCache1(RELOID, ObjectIdGetDatum(sequenceId));
		if (!HeapTupleIsValid(classtup))
			elog(ERROR, "cache lookup failed for relation %u", sequenceId);
		classtuple = (Form_pg_class) GETSTRUCT(classtup);

		/* Get the namespace */
		nspname = get_namespace_name(classtuple->relnamespace);
		if (!nspname)
			elog(ERROR, "cache lookup failed for namespace %u",
				 classtuple->relnamespace);

		/* And construct the result string */
		result = quote_qualified_identifier(nspname,
											NameStr(classtuple->relname));

		ReleaseSysCache(classtup);

		PG_RETURN_TEXT_P(string_to_text(result));
	}

	PG_RETURN_NULL();
}


/*
 * pg_get_functiondef
 *		Returns the complete "CREATE OR REPLACE FUNCTION ..." statement for
 *		the specified function.
 *
 * Note: if you change the output format of this function, be careful not
 * to break psql's rules (in \ef and \sf) for identifying the start of the
 * function body.  To wit: the function body starts on a line that begins
 * with "AS ", and no preceding line will look like that.
 */
Datum
pg_get_functiondef(PG_FUNCTION_ARGS)
{
	Oid			funcid = PG_GETARG_OID(0);
	StringInfoData buf;
	StringInfoData dq;
	HeapTuple	proctup;
	HeapTuple	langtup;
	Form_pg_proc proc;
	Form_pg_language lang;
	Datum		tmp;
	bool		isnull;
	const char *prosrc;
	const char *name;
	const char *nsp;
	float4		procost;
	int			oldlen;

	initStringInfo(&buf);

	/* Look up the function */
	proctup = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
	if (!HeapTupleIsValid(proctup))
		elog(ERROR, "cache lookup failed for function %u", funcid);
	proc = (Form_pg_proc) GETSTRUCT(proctup);
	name = NameStr(proc->proname);

	if (proc->proisagg)
		ereport(ERROR,
				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
				 errmsg("\"%s\" is an aggregate function", name)));

	/* Need its pg_language tuple for the language name */
	langtup = SearchSysCache1(LANGOID, ObjectIdGetDatum(proc->prolang));
	if (!HeapTupleIsValid(langtup))
		elog(ERROR, "cache lookup failed for language %u", proc->prolang);
	lang = (Form_pg_language) GETSTRUCT(langtup);

	/*
	 * We always qualify the function name, to ensure the right function gets
	 * replaced.
	 */
	nsp = get_namespace_name(proc->pronamespace);
	appendStringInfo(&buf, "CREATE OR REPLACE FUNCTION %s(",
					 quote_qualified_identifier(nsp, name));
	(void) print_function_arguments(&buf, proctup, false, true);
	appendStringInfoString(&buf, ")\n RETURNS ");
	print_function_rettype(&buf, proctup);
	appendStringInfo(&buf, "\n LANGUAGE %s\n",
					 quote_identifier(NameStr(lang->lanname)));

	/* Emit some miscellaneous options on one line */
	oldlen = buf.len;

	if (proc->proiswindow)
		appendStringInfoString(&buf, " WINDOW");
	switch (proc->provolatile)
	{
		case PROVOLATILE_IMMUTABLE:
			appendStringInfoString(&buf, " IMMUTABLE");
			break;
		case PROVOLATILE_STABLE:
			appendStringInfoString(&buf, " STABLE");
			break;
		case PROVOLATILE_VOLATILE:
			break;
	}
	if (proc->proisstrict)
		appendStringInfoString(&buf, " STRICT");
	if (proc->prosecdef)
		appendStringInfoString(&buf, " SECURITY DEFINER");

	/* This code for the default cost and rows should match functioncmds.c */
	if (proc->prolang == INTERNALlanguageId ||
		proc->prolang == ClanguageId)
		procost = 1;
	else
		procost = 100;
	if (proc->procost != procost)
		appendStringInfo(&buf, " COST %g", proc->procost);

	if (proc->prorows > 0 && proc->prorows != 1000)
		appendStringInfo(&buf, " ROWS %g", proc->prorows);

	if (oldlen != buf.len)
		appendStringInfoChar(&buf, '\n');

	/* Emit any proconfig options, one per line */
	tmp = SysCacheGetAttr(PROCOID, proctup, Anum_pg_proc_proconfig, &isnull);
	if (!isnull)
	{
		ArrayType  *a = DatumGetArrayTypeP(tmp);
		int			i;

		Assert(ARR_ELEMTYPE(a) == TEXTOID);
		Assert(ARR_NDIM(a) == 1);
		Assert(ARR_LBOUND(a)[0] == 1);

		for (i = 1; i <= ARR_DIMS(a)[0]; i++)
		{
			Datum		d;

			d = array_ref(a, 1, &i,
						  -1 /* varlenarray */ ,
						  -1 /* TEXT's typlen */ ,
						  false /* TEXT's typbyval */ ,
						  'i' /* TEXT's typalign */ ,
						  &isnull);
			if (!isnull)
			{
				char	   *configitem = TextDatumGetCString(d);
				char	   *pos;

				pos = strchr(configitem, '=');
				if (pos == NULL)
					continue;
				*pos++ = '\0';

				appendStringInfo(&buf, " SET %s TO ",
								 quote_identifier(configitem));

				/*
				 * Some GUC variable names are 'LIST' type and hence must not
				 * be quoted.
				 */
				if (pg_strcasecmp(configitem, "DateStyle") == 0
					|| pg_strcasecmp(configitem, "search_path") == 0)
					appendStringInfoString(&buf, pos);
				else
					simple_quote_literal(&buf, pos);
				appendStringInfoChar(&buf, '\n');
			}
		}
	}

	/* And finally the function definition ... */
	appendStringInfoString(&buf, "AS ");

	tmp = SysCacheGetAttr(PROCOID, proctup, Anum_pg_proc_probin, &isnull);
	if (!isnull)
	{
		simple_quote_literal(&buf, TextDatumGetCString(tmp));
		appendStringInfoString(&buf, ", ");		/* assume prosrc isn't null */
	}

	tmp = SysCacheGetAttr(PROCOID, proctup, Anum_pg_proc_prosrc, &isnull);
	if (isnull)
		elog(ERROR, "null prosrc");
	prosrc = TextDatumGetCString(tmp);

	/*
	 * We always use dollar quoting.  Figure out a suitable delimiter.
	 *
	 * Since the user is likely to be editing the function body string, we
	 * shouldn't use a short delimiter that he might easily create a conflict
	 * with.  Hence prefer "$function$", but extend if needed.
	 */
	initStringInfo(&dq);
	appendStringInfoString(&dq, "$function");
	while (strstr(prosrc, dq.data) != NULL)
		appendStringInfoChar(&dq, 'x');
	appendStringInfoChar(&dq, '$');

	appendStringInfoString(&buf, dq.data);
	appendStringInfoString(&buf, prosrc);
	appendStringInfoString(&buf, dq.data);

	appendStringInfoString(&buf, "\n");

	ReleaseSysCache(langtup);
	ReleaseSysCache(proctup);

	PG_RETURN_TEXT_P(string_to_text(buf.data));
}

/*
 * pg_get_function_arguments
 *		Get a nicely-formatted list of arguments for a function.
 *		This is everything that would go between the parentheses in
 *		CREATE FUNCTION.
 */
Datum
pg_get_function_arguments(PG_FUNCTION_ARGS)
{
	Oid			funcid = PG_GETARG_OID(0);
	StringInfoData buf;
	HeapTuple	proctup;

	initStringInfo(&buf);

	proctup = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
	if (!HeapTupleIsValid(proctup))
		elog(ERROR, "cache lookup failed for function %u", funcid);

	(void) print_function_arguments(&buf, proctup, false, true);

	ReleaseSysCache(proctup);

	PG_RETURN_TEXT_P(string_to_text(buf.data));
}

/*
 * pg_get_function_identity_arguments
 *		Get a formatted list of arguments for a function.
 *		This is everything that would go between the parentheses in
 *		ALTER FUNCTION, etc.  In particular, don't print defaults.
 */
Datum
pg_get_function_identity_arguments(PG_FUNCTION_ARGS)
{
	Oid			funcid = PG_GETARG_OID(0);
	StringInfoData buf;
	HeapTuple	proctup;

	initStringInfo(&buf);

	proctup = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
	if (!HeapTupleIsValid(proctup))
		elog(ERROR, "cache lookup failed for function %u", funcid);

	(void) print_function_arguments(&buf, proctup, false, false);

	ReleaseSysCache(proctup);

	PG_RETURN_TEXT_P(string_to_text(buf.data));
}

/*
 * pg_get_function_result
 *		Get a nicely-formatted version of the result type of a function.
 *		This is what would appear after RETURNS in CREATE FUNCTION.
 */
Datum
pg_get_function_result(PG_FUNCTION_ARGS)
{
	Oid			funcid = PG_GETARG_OID(0);
	StringInfoData buf;
	HeapTuple	proctup;

	initStringInfo(&buf);

	proctup = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
	if (!HeapTupleIsValid(proctup))
		elog(ERROR, "cache lookup failed for function %u", funcid);

	print_function_rettype(&buf, proctup);

	ReleaseSysCache(proctup);

	PG_RETURN_TEXT_P(string_to_text(buf.data));
}

/*
 * Guts of pg_get_function_result: append the function's return type
 * to the specified buffer.
 */
static void
print_function_rettype(StringInfo buf, HeapTuple proctup)
{
	Form_pg_proc proc = (Form_pg_proc) GETSTRUCT(proctup);
	int			ntabargs = 0;
	StringInfoData rbuf;

	initStringInfo(&rbuf);

	if (proc->proretset)
	{
		/* It might be a table function; try to print the arguments */
		appendStringInfoString(&rbuf, "TABLE(");
		ntabargs = print_function_arguments(&rbuf, proctup, true, false);
		if (ntabargs > 0)
			appendStringInfoString(&rbuf, ")");
		else
			resetStringInfo(&rbuf);
	}

	if (ntabargs == 0)
	{
		/* Not a table function, so do the normal thing */
		if (proc->proretset)
			appendStringInfoString(&rbuf, "SETOF ");
		appendStringInfoString(&rbuf, format_type_be(proc->prorettype));
	}

	appendStringInfoString(buf, rbuf.data);
}

/*
 * Common code for pg_get_function_arguments and pg_get_function_result:
 * append the desired subset of arguments to buf.  We print only TABLE
 * arguments when print_table_args is true, and all the others when it's false.
 * We print argument defaults only if print_defaults is true.
 * Function return value is the number of arguments printed.
 */
static int
print_function_arguments(StringInfo buf, HeapTuple proctup,
						 bool print_table_args, bool print_defaults)
{
	Form_pg_proc proc = (Form_pg_proc) GETSTRUCT(proctup);
	int			numargs;
	Oid		   *argtypes;
	char	  **argnames;
	char	   *argmodes;
	int			argsprinted;
	int			inputargno;
	int			nlackdefaults;
	ListCell   *nextargdefault = NULL;
	int			i;

	numargs = get_func_arg_info(proctup,
								&argtypes, &argnames, &argmodes);

	nlackdefaults = numargs;
	if (print_defaults && proc->pronargdefaults > 0)
	{
		Datum		proargdefaults;
		bool		isnull;

		proargdefaults = SysCacheGetAttr(PROCOID, proctup,
										 Anum_pg_proc_proargdefaults,
										 &isnull);
		if (!isnull)
		{
			char	   *str;
			List	   *argdefaults;

			str = TextDatumGetCString(proargdefaults);
			argdefaults = (List *) stringToNode(str);
			Assert(IsA(argdefaults, List));
			pfree(str);
			nextargdefault = list_head(argdefaults);
			/* nlackdefaults counts only *input* arguments lacking defaults */
			nlackdefaults = proc->pronargs - list_length(argdefaults);
		}
	}

	argsprinted = 0;
	inputargno = 0;
	for (i = 0; i < numargs; i++)
	{
		Oid			argtype = argtypes[i];
		char	   *argname = argnames ? argnames[i] : NULL;
		char		argmode = argmodes ? argmodes[i] : PROARGMODE_IN;
		const char *modename;
		bool		isinput;

		switch (argmode)
		{
			case PROARGMODE_IN:
				modename = "";
				isinput = true;
				break;
			case PROARGMODE_INOUT:
				modename = "INOUT ";
				isinput = true;
				break;
			case PROARGMODE_OUT:
				modename = "OUT ";
				isinput = false;
				break;
			case PROARGMODE_VARIADIC:
				modename = "VARIADIC ";
				isinput = true;
				break;
			case PROARGMODE_TABLE:
				modename = "";
				isinput = false;
				break;
			default:
				elog(ERROR, "invalid parameter mode '%c'", argmode);
				modename = NULL;	/* keep compiler quiet */
				isinput = false;
				break;
		}
		if (isinput)
			inputargno++;		/* this is a 1-based counter */

		if (print_table_args != (argmode == PROARGMODE_TABLE))
			continue;

		if (argsprinted)
			appendStringInfoString(buf, ", ");
		appendStringInfoString(buf, modename);
		if (argname && argname[0])
			appendStringInfo(buf, "%s ", quote_identifier(argname));
		appendStringInfoString(buf, format_type_be(argtype));
		if (print_defaults && isinput && inputargno > nlackdefaults)
		{
			Node	   *expr;

			Assert(nextargdefault != NULL);
			expr = (Node *) lfirst(nextargdefault);
			nextargdefault = lnext(nextargdefault);

			appendStringInfo(buf, " DEFAULT %s",
							 deparse_expression(expr, NIL, false, false));
		}
		argsprinted++;
	}

	return argsprinted;
}


/*
 * deparse_expression			- General utility for deparsing expressions
 *
 * calls deparse_expression_pretty with all prettyPrinting disabled
 */
char *
deparse_expression(Node *expr, List *dpcontext,
				   bool forceprefix, bool showimplicit)
{
	return deparse_expression_pretty(expr, dpcontext, forceprefix,
									 showimplicit, 0, 0);
}

/* ----------
 * deparse_expression_pretty	- General utility for deparsing expressions
 *
 * expr is the node tree to be deparsed.  It must be a transformed expression
 * tree (ie, not the raw output of gram.y).
 *
 * dpcontext is a list of deparse_namespace nodes representing the context
 * for interpreting Vars in the node tree.
 *
 * forceprefix is TRUE to force all Vars to be prefixed with their table names.
 *
 * showimplicit is TRUE to force all implicit casts to be shown explicitly.
 *
 * tries to pretty up the output according to prettyFlags and startIndent.
 *
 * The result is a palloc'd string.
 * ----------
 */
static char *
deparse_expression_pretty(Node *expr, List *dpcontext,
						  bool forceprefix, bool showimplicit,
						  int prettyFlags, int startIndent)
{
	StringInfoData buf;
	deparse_context context;

	initStringInfo(&buf);
	context.buf = &buf;
	context.namespaces = dpcontext;
	context.windowClause = NIL;
	context.windowTList = NIL;
	context.varprefix = forceprefix;
	context.prettyFlags = prettyFlags;
#ifdef PGXC
	context.finalise_aggs = false;
#endif /* PGXC */
	context.wrapColumn = WRAP_COLUMN_DEFAULT;
	context.indentLevel = startIndent;

	get_rule_expr(expr, &context, showimplicit);

	return buf.data;
}

/* ----------
 * deparse_context_for			- Build deparse context for a single relation
 *
 * Given the reference name (alias) and OID of a relation, build deparsing
 * context for an expression referencing only that relation (as varno 1,
 * varlevelsup 0).	This is sufficient for many uses of deparse_expression.
 * ----------
 */
List *
deparse_context_for(const char *aliasname, Oid relid)
{
	deparse_namespace *dpns;
	RangeTblEntry *rte;

	dpns = (deparse_namespace *) palloc0(sizeof(deparse_namespace));

	/* Build a minimal RTE for the rel */
	rte = makeNode(RangeTblEntry);
	rte->rtekind = RTE_RELATION;
	rte->relid = relid;
	rte->relkind = RELKIND_RELATION;	/* no need for exactness here */
	rte->eref = makeAlias(aliasname, NIL);
	rte->inh = false;
	rte->inFromCl = true;

	/* Build one-element rtable */
	dpns->rtable = list_make1(rte);
	dpns->ctes = NIL;
#ifdef PGXC
	dpns->remotequery = false;
#endif

	/* Return a one-deep namespace stack */
	return list_make1(dpns);
}

/*
 * deparse_context_for_planstate	- Build deparse context for a plan
 *
 * When deparsing an expression in a Plan tree, we might have to resolve
 * OUTER_VAR, INNER_VAR, or INDEX_VAR references.  To do this, the caller must
 * provide the parent PlanState node.  Then OUTER_VAR and INNER_VAR references
 * can be resolved by drilling down into the left and right child plans.
 * Similarly, INDEX_VAR references can be resolved by reference to the
 * indextlist given in the parent IndexOnlyScan node.  (Note that we don't
 * currently support deparsing of indexquals in regular IndexScan or
 * BitmapIndexScan nodes; for those, we can only deparse the indexqualorig
 * fields, which won't contain INDEX_VAR Vars.)
 *
 * Note: planstate really ought to be declared as "PlanState *", but we use
 * "Node *" to avoid having to include execnodes.h in builtins.h.
 *
 * The ancestors list is a list of the PlanState's parent PlanStates, the
 * most-closely-nested first.  This is needed to resolve PARAM_EXEC Params.
 * Note we assume that all the PlanStates share the same rtable.
 *
 * The plan's rangetable list must also be passed.  We actually prefer to use
 * the rangetable to resolve simple Vars, but the plan inputs are necessary
 * for Vars with special varnos.
 */
List *
deparse_context_for_planstate(Node *planstate, List *ancestors,
							  List *rtable)
{
	deparse_namespace *dpns;

	dpns = (deparse_namespace *) palloc0(sizeof(deparse_namespace));

	/* Initialize fields that stay the same across the whole plan tree */
	dpns->rtable = rtable;
	dpns->ctes = NIL;
#ifdef PGXC
	dpns->remotequery = false;
#endif

	/* Set our attention on the specific plan node passed in */
	set_deparse_planstate(dpns, (PlanState *) planstate);
	dpns->ancestors = ancestors;

	/* Return a one-deep namespace stack */
	return list_make1(dpns);
}

/*
 * set_deparse_planstate: set up deparse_namespace to parse subexpressions
 * of a given PlanState node
 *
 * This sets the planstate, outer_planstate, inner_planstate, outer_tlist,
 * inner_tlist, and index_tlist fields.  Caller is responsible for adjusting
 * the ancestors list if necessary.  Note that the rtable and ctes fields do
 * not need to change when shifting attention to different plan nodes in a
 * single plan tree.
 */
static void
set_deparse_planstate(deparse_namespace *dpns, PlanState *ps)
{
	dpns->planstate = ps;

	/*
	 * We special-case Append and MergeAppend to pretend that the first child
	 * plan is the OUTER referent; we have to interpret OUTER Vars in their
	 * tlists according to one of the children, and the first one is the most
	 * natural choice.	Likewise special-case ModifyTable to pretend that the
	 * first child plan is the OUTER referent; this is to support RETURNING
	 * lists containing references to non-target relations.
	 */
	if (IsA(ps, AppendState))
		dpns->outer_planstate = ((AppendState *) ps)->appendplans[0];
	else if (IsA(ps, MergeAppendState))
		dpns->outer_planstate = ((MergeAppendState *) ps)->mergeplans[0];
	else if (IsA(ps, ModifyTableState))
		dpns->outer_planstate = ((ModifyTableState *) ps)->mt_plans[0];
	else
		dpns->outer_planstate = outerPlanState(ps);

	if (dpns->outer_planstate)
		dpns->outer_tlist = dpns->outer_planstate->plan->targetlist;
	else
		dpns->outer_tlist = NIL;

	/*
	 * For a SubqueryScan, pretend the subplan is INNER referent.  (We don't
	 * use OUTER because that could someday conflict with the normal meaning.)
	 * Likewise, for a CteScan, pretend the subquery's plan is INNER referent.
	 */
	if (IsA(ps, SubqueryScanState))
		dpns->inner_planstate = ((SubqueryScanState *) ps)->subplan;
	else if (IsA(ps, CteScanState))
		dpns->inner_planstate = ((CteScanState *) ps)->cteplanstate;
	else
		dpns->inner_planstate = innerPlanState(ps);

	if (dpns->inner_planstate)
		dpns->inner_tlist = dpns->inner_planstate->plan->targetlist;
	else
		dpns->inner_tlist = NIL;

	/* index_tlist is set only if it's an IndexOnlyScan */
	if (IsA(ps->plan, IndexOnlyScan))
		dpns->index_tlist = ((IndexOnlyScan *) ps->plan)->indextlist;
	else
		dpns->index_tlist = NIL;
}

#ifdef PGXC
/*
 * This is a special case deparse context to be used at the planning time to
 * generate query strings and expressions for remote shipping.
 *
 * XXX We should be careful while using this since the support is quite
 * limited. The only supported use case at this point is for remote join
 * reduction and some simple plan trees rooted by Agg node having a single
 * RemoteQuery node as leftree.
 */
List *
deparse_context_for_plan(Node *plan, List *ancestors,
							  List *rtable)
{
	deparse_namespace *dpns;

	dpns = (deparse_namespace *) palloc0(sizeof(deparse_namespace));

	/* Initialize fields that stay the same across the whole plan tree */
	dpns->rtable = rtable;
	dpns->ctes = NIL;
	dpns->remotequery = false;

	/* Set our attention on the specific plan node passed in */
	set_deparse_plan(dpns, (Plan *) plan);
	dpns->ancestors = ancestors;

	/* Return a one-deep namespace stack */
	return list_make1(dpns);
}

/*
 * Set deparse context for Plan. Only those plan nodes which are immediate (or
 * through simple nodes) parents of RemoteQuery nodes are supported right now.
 *
 * This is a kind of work-around since the new deparse interface (since 9.1)
 * expects a PlanState node. But planstates are instantiated only at execution
 * time when InitPlan is called. But we are required to deparse the query
 * during planning time, so we hand-cook these dummy PlanState nodes instead of
 * init-ing the plan. Another approach could have been to delay the query
 * generation to the execution time, but we are not yet sure if this can be
 * safely done, especially for remote join reduction.
 */
static void
set_deparse_plan(deparse_namespace *dpns, Plan *plan)
{

	if (IsA(plan, NestLoop))
	{
		NestLoop *nestloop = (NestLoop *) plan;

		dpns->planstate = (PlanState *) makeNode(NestLoopState);
		dpns->planstate->plan = plan;

		dpns->outer_planstate = (PlanState *) makeNode(PlanState);
		dpns->outer_planstate->plan = nestloop->join.plan.lefttree;

		dpns->inner_planstate = (PlanState *) makeNode(PlanState);
		dpns->inner_planstate->plan = nestloop->join.plan.righttree;
	}
	else if (IsA(plan, RemoteQuery))
	{
		dpns->planstate = (PlanState *) makeNode(PlanState);
		dpns->planstate->plan = plan;
	}
	else if (IsA(plan, Agg) || IsA(plan, Group))
	{
		/*
		 * We expect plan tree as Group/Agg->Sort->Result->Material->RemoteQuery,
		 * Result, Material nodes are optional. Sort is compulsory for Group but not
		 * for Agg.
		 * anything else is not handled right now.
		 */
		Plan *temp_plan = plan->lefttree;
		Plan *remote_scan = NULL;

		if (temp_plan && IsA(temp_plan, Sort))
			temp_plan = temp_plan->lefttree;
		if (temp_plan && IsA(temp_plan, Result))
			temp_plan = temp_plan->lefttree;
		if (temp_plan && IsA(temp_plan, Material))
			temp_plan = temp_plan->lefttree;
		if (temp_plan && IsA(temp_plan, RemoteQuery))
			remote_scan = temp_plan;

		if (!remote_scan)
			elog(ERROR, "Deparse of this query at planning is not supported yet");

		dpns->planstate = (PlanState *) makeNode(PlanState);
		dpns->planstate->plan = plan;
	}
	else
		elog(ERROR, "Deparse of this query at planning not supported yet");
}

#endif
/*
 * push_child_plan: temporarily transfer deparsing attention to a child plan
 *
 * When expanding an OUTER_VAR or INNER_VAR reference, we must adjust the
 * deparse context in case the referenced expression itself uses
 * OUTER_VAR/INNER_VAR.  We modify the top stack entry in-place to avoid
 * affecting levelsup issues (although in a Plan tree there really shouldn't
 * be any).
 *
 * Caller must provide a local deparse_namespace variable to save the
 * previous state for pop_child_plan.
 */
static void
push_child_plan(deparse_namespace *dpns, PlanState *ps,
				deparse_namespace *save_dpns)
{
	/* Save state for restoration later */
	*save_dpns = *dpns;

	/*
	 * Currently we don't bother to adjust the ancestors list, because an
	 * OUTER_VAR or INNER_VAR reference really shouldn't contain any Params
	 * that would be set by the parent node itself.  If we did want to adjust
	 * the list, lcons'ing dpns->planstate onto dpns->ancestors would be the
	 * appropriate thing --- and pop_child_plan would need to undo the change
	 * to the list.
	 */

	/* Set attention on selected child */
	set_deparse_planstate(dpns, ps);
}

/*
 * pop_child_plan: undo the effects of push_child_plan
 */
static void
pop_child_plan(deparse_namespace *dpns, deparse_namespace *save_dpns)
{
	/* Restore fields changed by push_child_plan */
	*dpns = *save_dpns;
}

/*
 * push_ancestor_plan: temporarily transfer deparsing attention to an
 * ancestor plan
 *
 * When expanding a Param reference, we must adjust the deparse context
 * to match the plan node that contains the expression being printed;
 * otherwise we'd fail if that expression itself contains a Param or
 * OUTER_VAR/INNER_VAR/INDEX_VAR variable.
 *
 * The target ancestor is conveniently identified by the ListCell holding it
 * in dpns->ancestors.
 *
 * Caller must provide a local deparse_namespace variable to save the
 * previous state for pop_ancestor_plan.
 */
static void
push_ancestor_plan(deparse_namespace *dpns, ListCell *ancestor_cell,
				   deparse_namespace *save_dpns)
{
	PlanState  *ps = (PlanState *) lfirst(ancestor_cell);
	List	   *ancestors;

	/* Save state for restoration later */
	*save_dpns = *dpns;

	/* Build a new ancestor list with just this node's ancestors */
	ancestors = NIL;
	while ((ancestor_cell = lnext(ancestor_cell)) != NULL)
		ancestors = lappend(ancestors, lfirst(ancestor_cell));
	dpns->ancestors = ancestors;

	/* Set attention on selected ancestor */
	set_deparse_planstate(dpns, ps);
}

/*
 * pop_ancestor_plan: undo the effects of push_ancestor_plan
 */
static void
pop_ancestor_plan(deparse_namespace *dpns, deparse_namespace *save_dpns)
{
	/* Free the ancestor list made in push_ancestor_plan */
	list_free(dpns->ancestors);

	/* Restore fields changed by push_ancestor_plan */
	*dpns = *save_dpns;
}


/* ----------
 * make_ruledef			- reconstruct the CREATE RULE command
 *				  for a given pg_rewrite tuple
 * ----------
 */
static void
make_ruledef(StringInfo buf, HeapTuple ruletup, TupleDesc rulettc,
			 int prettyFlags)
{
	char	   *rulename;
	char		ev_type;
	Oid			ev_class;
	int2		ev_attr;
	bool		is_instead;
	char	   *ev_qual;
	char	   *ev_action;
	List	   *actions = NIL;
	int			fno;
	Datum		dat;
	bool		isnull;

	/*
	 * Get the attribute values from the rules tuple
	 */
	fno = SPI_fnumber(rulettc, "rulename");
	dat = SPI_getbinval(ruletup, rulettc, fno, &isnull);
	Assert(!isnull);
	rulename = NameStr(*(DatumGetName(dat)));

	fno = SPI_fnumber(rulettc, "ev_type");
	dat = SPI_getbinval(ruletup, rulettc, fno, &isnull);
	Assert(!isnull);
	ev_type = DatumGetChar(dat);

	fno = SPI_fnumber(rulettc, "ev_class");
	dat = SPI_getbinval(ruletup, rulettc, fno, &isnull);
	Assert(!isnull);
	ev_class = DatumGetObjectId(dat);

	fno = SPI_fnumber(rulettc, "ev_attr");
	dat = SPI_getbinval(ruletup, rulettc, fno, &isnull);
	Assert(!isnull);
	ev_attr = DatumGetInt16(dat);

	fno = SPI_fnumber(rulettc, "is_instead");
	dat = SPI_getbinval(ruletup, rulettc, fno, &isnull);
	Assert(!isnull);
	is_instead = DatumGetBool(dat);

	/* these could be nulls */
	fno = SPI_fnumber(rulettc, "ev_qual");
	ev_qual = SPI_getvalue(ruletup, rulettc, fno);

	fno = SPI_fnumber(rulettc, "ev_action");
	ev_action = SPI_getvalue(ruletup, rulettc, fno);
	if (ev_action != NULL)
		actions = (List *) stringToNode(ev_action);

	/*
	 * Build the rules definition text
	 */
	appendStringInfo(buf, "CREATE RULE %s AS",
					 quote_identifier(rulename));

	if (prettyFlags & PRETTYFLAG_INDENT)
		appendStringInfoString(buf, "\n    ON ");
	else
		appendStringInfoString(buf, " ON ");

	/* The event the rule is fired for */
	switch (ev_type)
	{
		case '1':
			appendStringInfo(buf, "SELECT");
			break;

		case '2':
			appendStringInfo(buf, "UPDATE");
			break;

		case '3':
			appendStringInfo(buf, "INSERT");
			break;

		case '4':
			appendStringInfo(buf, "DELETE");
			break;

		default:
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
					 errmsg("rule \"%s\" has unsupported event type %d",
							rulename, ev_type)));
			break;
	}

	/* The relation the rule is fired on */
	appendStringInfo(buf, " TO %s", generate_relation_name(ev_class, NIL));
	if (ev_attr > 0)
		appendStringInfo(buf, ".%s",
						 quote_identifier(get_relid_attribute_name(ev_class,
																   ev_attr)));

	/* If the rule has an event qualification, add it */
	if (ev_qual == NULL)
		ev_qual = "";
	if (strlen(ev_qual) > 0 && strcmp(ev_qual, "<>") != 0)
	{
		Node	   *qual;
		Query	   *query;
		deparse_context context;
		deparse_namespace dpns;

		if (prettyFlags & PRETTYFLAG_INDENT)
			appendStringInfoString(buf, "\n  ");
		appendStringInfo(buf, " WHERE ");

		qual = stringToNode(ev_qual);

		/*
		 * We need to make a context for recognizing any Vars in the qual
		 * (which can only be references to OLD and NEW).  Use the rtable of
		 * the first query in the action list for this purpose.
		 */
		query = (Query *) linitial(actions);

		/*
		 * If the action is INSERT...SELECT, OLD/NEW have been pushed down
		 * into the SELECT, and that's what we need to look at. (Ugly kluge
		 * ... try to fix this when we redesign querytrees.)
		 */
		query = getInsertSelectQuery(query, NULL);

		/* Must acquire locks right away; see notes in get_query_def() */
		AcquireRewriteLocks(query, false);

		context.buf = buf;
		context.namespaces = list_make1(&dpns);
		context.windowClause = NIL;
		context.windowTList = NIL;
		context.varprefix = (list_length(query->rtable) != 1);
		context.prettyFlags = prettyFlags;
		context.wrapColumn = WRAP_COLUMN_DEFAULT;
		context.indentLevel = PRETTYINDENT_STD;
#ifdef PGXC
		context.finalise_aggs = false;
#endif /* PGXC */

		memset(&dpns, 0, sizeof(dpns));
		dpns.rtable = query->rtable;
		dpns.ctes = query->cteList;
#ifdef PGXC
		dpns.remotequery = false;
#endif
		get_rule_expr(qual, &context, false);
	}

	appendStringInfo(buf, " DO ");

	/* The INSTEAD keyword (if so) */
	if (is_instead)
		appendStringInfo(buf, "INSTEAD ");

	/* Finally the rules actions */
	if (list_length(actions) > 1)
	{
		ListCell   *action;
		Query	   *query;

		appendStringInfo(buf, "(");
		foreach(action, actions)
		{
			query = (Query *) lfirst(action);
			get_query_def(query, buf, NIL, NULL,
						  prettyFlags, WRAP_COLUMN_DEFAULT, 0
#ifdef PGXC
			, false, false
#endif /* PGXC */
			);
			if (prettyFlags)
				appendStringInfo(buf, ";\n");
			else
				appendStringInfo(buf, "; ");
		}
		appendStringInfo(buf, ");");
	}
	else if (list_length(actions) == 0)
	{
		appendStringInfo(buf, "NOTHING;");
	}
	else
	{
		Query	   *query;

		query = (Query *) linitial(actions);
		get_query_def(query, buf, NIL, NULL,
					  prettyFlags, WRAP_COLUMN_DEFAULT, 0
#ifdef PGXC
						, false, false
#endif /* PGXC */
		);
		appendStringInfo(buf, ";");
	}
}


/* ----------
 * make_viewdef			- reconstruct the SELECT part of a
 *				  view rewrite rule
 * ----------
 */
static void
make_viewdef(StringInfo buf, HeapTuple ruletup, TupleDesc rulettc,
			 int prettyFlags, int wrapColumn)
{
	Query	   *query;
	char		ev_type;
	Oid			ev_class;
	int2		ev_attr;
	bool		is_instead;
	char	   *ev_qual;
	char	   *ev_action;
	List	   *actions = NIL;
	Relation	ev_relation;
	int			fno;
	bool		isnull;

	/*
	 * Get the attribute values from the rules tuple
	 */
	fno = SPI_fnumber(rulettc, "ev_type");
	ev_type = (char) SPI_getbinval(ruletup, rulettc, fno, &isnull);

	fno = SPI_fnumber(rulettc, "ev_class");
	ev_class = (Oid) SPI_getbinval(ruletup, rulettc, fno, &isnull);

	fno = SPI_fnumber(rulettc, "ev_attr");
	ev_attr = (int2) SPI_getbinval(ruletup, rulettc, fno, &isnull);

	fno = SPI_fnumber(rulettc, "is_instead");
	is_instead = (bool) SPI_getbinval(ruletup, rulettc, fno, &isnull);

	fno = SPI_fnumber(rulettc, "ev_qual");
	ev_qual = SPI_getvalue(ruletup, rulettc, fno);

	fno = SPI_fnumber(rulettc, "ev_action");
	ev_action = SPI_getvalue(ruletup, rulettc, fno);
	if (ev_action != NULL)
		actions = (List *) stringToNode(ev_action);

	if (list_length(actions) != 1)
	{
		appendStringInfo(buf, "Not a view");
		return;
	}

	query = (Query *) linitial(actions);

	if (ev_type != '1' || ev_attr >= 0 || !is_instead ||
		strcmp(ev_qual, "<>") != 0 || query->commandType != CMD_SELECT)
	{
		appendStringInfo(buf, "Not a view");
		return;
	}

	ev_relation = heap_open(ev_class, AccessShareLock);

	get_query_def(query, buf, NIL, RelationGetDescr(ev_relation),
				  prettyFlags, wrapColumn, 0
#ifdef PGXC
				  , false, false
#endif /* PGXC */
				  );
	appendStringInfo(buf, ";");

	heap_close(ev_relation, AccessShareLock);
}


#ifdef PGXC
/* ----------
 * deparse_query			- Parse back one query parsetree
 *
 * Purpose of this function is to build up statement for a RemoteQuery
 * The query generated has all object names schema-qualified. This is
 * done by temporarily setting search_path to NIL.
 * It calls get_query_def without pretty print flags.
 * ----------
 */
void
deparse_query(Query *query, StringInfo buf, List *parentnamespace,
				bool finalise_aggs, bool sortgroup_colno)
{
	OverrideSearchPath	*tmp_search_path;
	List				*schema_list;
	ListCell			*schema;

	/*
	 * Before deparsing the query, set the search_patch to NIL so that all the
	 * object names in the deparsed query are schema qualified. This is required
	 * so as to not have any dependency on current search_path. For e.g the same
	 * remote query can be used even if search_path changes between two executes
	 * of a prepared statement.
	 * Note: We do not apply the above solution for temp tables for reasons shown
	 * in the below comment.
	 */
	tmp_search_path = GetOverrideSearchPath(CurrentMemoryContext);

	tmp_search_path->addTemp = true;
	schema_list = tmp_search_path->schemas;
	foreach(schema, schema_list)
	{
		if (isTempNamespace(lfirst_oid(schema)))
		{
			 /* Is pg_temp the very first item ? If no, that means temp objects
			  * should be qualified, otherwise the object name would possibly
			  * be resolved from some other schema. We force schema
			  * qualification by making sure the overridden search_path does not
			  * have pg_temp implicitly added.
			  * Why do we not *always* let the pg_temp qualification be there ?
			  * Because the pg_temp schema name always gets deparsed into the
			  * actual temp schema names like pg_temp_[1-9]*, and not the dummy
			  * name pg_temp. And we do not want to use these names because
			  * they are specific to the local node. pg_temp_2.obj1 at node 1
			  * may be present in pg_temp_3 at node2.
			  */
			if (list_head(schema_list) != schema)
				tmp_search_path->addTemp = false;

			break;
		}
	}

	tmp_search_path->schemas = NIL;
	PushOverrideSearchPath(tmp_search_path);

	get_query_def(query, buf, parentnamespace, NULL, 0, WRAP_COLUMN_DEFAULT,
					0, finalise_aggs, sortgroup_colno);

	PopOverrideSearchPath();
}
#endif
/* ----------
 * get_query_def			- Parse back one query parsetree
 *
 * If resultDesc is not NULL, then it is the output tuple descriptor for
 * the view represented by a SELECT query.
 * ----------
 */
static void
get_query_def(Query *query, StringInfo buf, List *parentnamespace,
			  TupleDesc resultDesc,
			  int prettyFlags, int wrapColumn, int startIndent
#ifdef PGXC
				, bool finalise_aggs, bool sortgroup_colno
#endif /* PGXC */
			  )
{
	deparse_context context;
	deparse_namespace dpns;

	/*
	 * Before we begin to examine the query, acquire locks on referenced
	 * relations, and fix up deleted columns in JOIN RTEs.	This ensures
	 * consistent results.	Note we assume it's OK to scribble on the passed
	 * querytree!
	 */
	AcquireRewriteLocks(query, false);

	context.buf = buf;
	context.namespaces = lcons(&dpns, list_copy(parentnamespace));
	context.windowClause = NIL;
	context.windowTList = NIL;
	context.varprefix = (parentnamespace != NIL ||
						 list_length(query->rtable) != 1);
	context.prettyFlags = prettyFlags;
	context.wrapColumn = wrapColumn;
	context.indentLevel = startIndent;
#ifdef PGXC
	context.finalise_aggs = finalise_aggs;
	context.sortgroup_colno = sortgroup_colno;
#endif /* PGXC */

	memset(&dpns, 0, sizeof(dpns));
	dpns.rtable = query->rtable;
	dpns.ctes = query->cteList;
#ifdef PGXC
	dpns.remotequery = false;
#endif

	switch (query->commandType)
	{
		case CMD_SELECT:
			get_select_query_def(query, &context, resultDesc);
			break;

		case CMD_UPDATE:
			get_update_query_def(query, &context);
			break;

		case CMD_INSERT:
			get_insert_query_def(query, &context);
			break;

		case CMD_DELETE:
			get_delete_query_def(query, &context);
			break;

		case CMD_NOTHING:
			appendStringInfo(buf, "NOTHING");
			break;

		case CMD_UTILITY:
			get_utility_query_def(query, &context);
			break;

		default:
			elog(ERROR, "unrecognized query command type: %d",
				 query->commandType);
			break;
	}
}

/* ----------
 * get_values_def			- Parse back a VALUES list
 * ----------
 */
static void
get_values_def(List *values_lists, deparse_context *context)
{
	StringInfo	buf = context->buf;
	bool		first_list = true;
	ListCell   *vtl;

	appendStringInfoString(buf, "VALUES ");

	foreach(vtl, values_lists)
	{
		List	   *sublist = (List *) lfirst(vtl);
		bool		first_col = true;
		ListCell   *lc;

		if (first_list)
			first_list = false;
		else
			appendStringInfoString(buf, ", ");

		appendStringInfoChar(buf, '(');
		foreach(lc, sublist)
		{
			Node	   *col = (Node *) lfirst(lc);

			if (first_col)
				first_col = false;
			else
				appendStringInfoChar(buf, ',');

			/*
			 * Strip any top-level nodes representing indirection assignments,
			 * then print the result.
			 */
			get_rule_expr(processIndirection(col, context, false),
						  context, false);
		}
		appendStringInfoChar(buf, ')');
	}
}

/* ----------
 * get_with_clause			- Parse back a WITH clause
 * ----------
 */
static void
get_with_clause(Query *query, deparse_context *context)
{
	StringInfo	buf = context->buf;
	const char *sep;
	ListCell   *l;

	if (query->cteList == NIL)
		return;

	if (PRETTY_INDENT(context))
	{
		context->indentLevel += PRETTYINDENT_STD;
		appendStringInfoChar(buf, ' ');
	}

	if (query->hasRecursive)
		sep = "WITH RECURSIVE ";
	else
		sep = "WITH ";
	foreach(l, query->cteList)
	{
		CommonTableExpr *cte = (CommonTableExpr *) lfirst(l);

		appendStringInfoString(buf, sep);
		appendStringInfoString(buf, quote_identifier(cte->ctename));
		if (cte->aliascolnames)
		{
			bool		first = true;
			ListCell   *col;

			appendStringInfoChar(buf, '(');
			foreach(col, cte->aliascolnames)
			{
				if (first)
					first = false;
				else
					appendStringInfoString(buf, ", ");
				appendStringInfoString(buf,
									   quote_identifier(strVal(lfirst(col))));
			}
			appendStringInfoChar(buf, ')');
		}
		appendStringInfoString(buf, " AS (");
		if (PRETTY_INDENT(context))
			appendContextKeyword(context, "", 0, 0, 0);
		get_query_def((Query *) cte->ctequery, buf, context->namespaces, NULL,
					  context->prettyFlags, context->wrapColumn,
					  context->indentLevel
#ifdef PGXC
					  , context->finalise_aggs, context->sortgroup_colno
#endif /* PGXC */
					  );
		if (PRETTY_INDENT(context))
			appendContextKeyword(context, "", 0, 0, 0);
		appendStringInfoChar(buf, ')');
		sep = ", ";
	}

	if (PRETTY_INDENT(context))
	{
		context->indentLevel -= PRETTYINDENT_STD;
		appendContextKeyword(context, "", 0, 0, 0);
	}
	else
		appendStringInfoChar(buf, ' ');
}

/* ----------
 * get_select_query_def			- Parse back a SELECT parsetree
 * ----------
 */
static void
get_select_query_def(Query *query, deparse_context *context,
					 TupleDesc resultDesc)
{
	StringInfo	buf = context->buf;
	List	   *save_windowclause;
	List	   *save_windowtlist;
	bool		force_colno;
	ListCell   *l;

	/* Insert the WITH clause if given */
	get_with_clause(query, context);

	/* Set up context for possible window functions */
	save_windowclause = context->windowClause;
	context->windowClause = query->windowClause;
	save_windowtlist = context->windowTList;
	context->windowTList = query->targetList;

	/*
	 * If the Query node has a setOperations tree, then it's the top level of
	 * a UNION/INTERSECT/EXCEPT query; only the WITH, ORDER BY and LIMIT
	 * fields are interesting in the top query itself.
	 */
	if (query->setOperations)
	{
		get_setop_query(query->setOperations, query, context, resultDesc);
		/* ORDER BY clauses must be simple in this case */
		force_colno = true;
	}
	else
	{
		get_basic_select_query(query, context, resultDesc);
		force_colno = false;
	}

	/* Add the ORDER BY clause if given */
	if (query->sortClause != NIL)
	{
		appendContextKeyword(context, " ORDER BY ",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
		get_rule_orderby(query->sortClause, query->targetList,
						 force_colno, context);
	}

	/* Add the LIMIT clause if given */
	if (query->limitOffset != NULL)
	{
		appendContextKeyword(context, " OFFSET ",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 0);
		get_rule_expr(query->limitOffset, context, false);
	}
	if (query->limitCount != NULL)
	{
		appendContextKeyword(context, " LIMIT ",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 0);
		if (IsA(query->limitCount, Const) &&
			((Const *) query->limitCount)->constisnull)
			appendStringInfo(buf, "ALL");
		else
			get_rule_expr(query->limitCount, context, false);
	}

	/* Add FOR UPDATE/SHARE clauses if present */
	if (query->hasForUpdate)
	{
		foreach(l, query->rowMarks)
		{
			RowMarkClause *rc = (RowMarkClause *) lfirst(l);
			RangeTblEntry *rte = rt_fetch(rc->rti, query->rtable);

			/* don't print implicit clauses */
			if (rc->pushedDown)
				continue;

			if (rc->forUpdate)
				appendContextKeyword(context, " FOR UPDATE",
									 -PRETTYINDENT_STD, PRETTYINDENT_STD, 0);
			else
				appendContextKeyword(context, " FOR SHARE",
									 -PRETTYINDENT_STD, PRETTYINDENT_STD, 0);
			appendStringInfo(buf, " OF %s",
							 quote_identifier(rte->eref->aliasname));
			if (rc->noWait)
				appendStringInfo(buf, " NOWAIT");
		}
	}

	context->windowClause = save_windowclause;
	context->windowTList = save_windowtlist;
}

static void
get_basic_select_query(Query *query, deparse_context *context,
					   TupleDesc resultDesc)
{
	StringInfo	buf = context->buf;
	char	   *sep;
	ListCell   *l;

	if (PRETTY_INDENT(context))
	{
		context->indentLevel += PRETTYINDENT_STD;
		appendStringInfoChar(buf, ' ');
	}

	/*
	 * If the query looks like SELECT * FROM (VALUES ...), then print just the
	 * VALUES part.  This reverses what transformValuesClause() did at parse
	 * time.  If the jointree contains just a single VALUES RTE, we assume
	 * this case applies (without looking at the targetlist...)
	 */
	if (list_length(query->jointree->fromlist) == 1)
	{
		RangeTblRef *rtr = (RangeTblRef *) linitial(query->jointree->fromlist);

		if (IsA(rtr, RangeTblRef))
		{
			RangeTblEntry *rte = rt_fetch(rtr->rtindex, query->rtable);

			if (rte->rtekind == RTE_VALUES)
			{
				get_values_def(rte->values_lists, context);
				return;
			}
		}
	}

	/*
	 * Build up the query string - first we say SELECT
	 */
	appendStringInfo(buf, "SELECT");

	/* Add the DISTINCT clause if given */
	if (query->distinctClause != NIL)
	{
		if (query->hasDistinctOn)
		{
			appendStringInfo(buf, " DISTINCT ON (");
			sep = "";
			foreach(l, query->distinctClause)
			{
				SortGroupClause *srt = (SortGroupClause *) lfirst(l);

				appendStringInfoString(buf, sep);
				get_rule_sortgroupclause(srt, query->targetList,
										 false, context);
				sep = ", ";
			}
			appendStringInfo(buf, ")");
		}
		else
			appendStringInfo(buf, " DISTINCT");
	}

	/* Then we tell what to select (the targetlist) */
	get_target_list(query->targetList, context, resultDesc);

	/* Add the FROM clause if needed */
	get_from_clause(query, " FROM ", context);

	/* Add the WHERE clause if given */
	if (query->jointree->quals != NULL)
	{
		appendContextKeyword(context, " WHERE ",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
		get_rule_expr(query->jointree->quals, context, false);
	}

	/* Add the GROUP BY clause if given */
	if (query->groupClause != NULL)
	{
		appendContextKeyword(context, " GROUP BY ",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
		sep = "";
		foreach(l, query->groupClause)
		{
			SortGroupClause *grp = (SortGroupClause *) lfirst(l);

			appendStringInfoString(buf, sep);
			get_rule_sortgroupclause(grp, query->targetList,
									 false, context);
			sep = ", ";
		}
	}

	/* Add the HAVING clause if given */
	if (query->havingQual != NULL)
	{
		appendContextKeyword(context, " HAVING ",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 0);
		get_rule_expr(query->havingQual, context, false);
	}

	/* Add the WINDOW clause if needed */
	if (query->windowClause != NIL)
		get_rule_windowclause(query, context);
}

/* ----------
 * get_target_list			- Parse back a SELECT target list
 *
 * This is also used for RETURNING lists in INSERT/UPDATE/DELETE.
 * ----------
 */
static void
get_target_list(List *targetList, deparse_context *context,
				TupleDesc resultDesc)
{
	StringInfo	buf = context->buf;
	StringInfoData targetbuf;
	bool		last_was_multiline = false;
	char	   *sep;
	int			colno;
	ListCell   *l;
#ifdef PGXC
	bool no_targetlist = true;
#endif

	/* we use targetbuf to hold each TLE's text temporarily */
	initStringInfo(&targetbuf);

	sep = " ";
	colno = 0;
	foreach(l, targetList)
	{
		TargetEntry *tle = (TargetEntry *) lfirst(l);
		char	   *colname;
		char	   *attname;

		if (tle->resjunk)
			continue;			/* ignore junk entries */

#ifdef PGXC
		/* Found at least one element in the target list */
		if (no_targetlist)
			no_targetlist = false;
#endif

		appendStringInfoString(buf, sep);
		sep = ", ";
		colno++;

		/*
		 * Put the new field text into targetbuf so we can decide after we've
		 * got it whether or not it needs to go on a new line.
		 */
		resetStringInfo(&targetbuf);
		context->buf = &targetbuf;

		/*
		 * We special-case Var nodes rather than using get_rule_expr. This is
		 * needed because get_rule_expr will display a whole-row Var as
		 * "foo.*", which is the preferred notation in most contexts, but at
		 * the top level of a SELECT list it's not right (the parser will
		 * expand that notation into multiple columns, yielding behavior
		 * different from a whole-row Var).  We need to call get_variable
		 * directly so that we can tell it to do the right thing.
		 */
		if (tle->expr && IsA(tle->expr, Var))
		{
			attname = get_variable((Var *) tle->expr, 0, true, context);
		}
		else
		{
			get_rule_expr((Node *) tle->expr, context, true);
			/* We'll show the AS name unless it's this: */
			attname = "?column?";
		}

		/*
		 * Figure out what the result column should be called.	In the context
		 * of a view, use the view's tuple descriptor (so as to pick up the
		 * effects of any column RENAME that's been done on the view).
		 * Otherwise, just use what we can find in the TLE.
		 */
		if (resultDesc && colno <= resultDesc->natts)
			colname = NameStr(resultDesc->attrs[colno - 1]->attname);
		else
			colname = tle->resname;

		/* Show AS unless the column's name is correct as-is */
		if (colname)			/* resname could be NULL */
		{
			if (attname == NULL || strcmp(attname, colname) != 0)
				appendStringInfo(&targetbuf, " AS %s", quote_identifier(colname));
		}

		/* Restore context's output buffer */
		context->buf = buf;

		/* Consider line-wrapping if enabled */
		if (PRETTY_INDENT(context) && context->wrapColumn >= 0)
		{
			int			leading_nl_pos = -1;
			char	   *trailing_nl;
			int			pos;

			/* Does the new field start with whitespace plus a new line? */
			for (pos = 0; pos < targetbuf.len; pos++)
			{
				if (targetbuf.data[pos] == '\n')
				{
					leading_nl_pos = pos;
					break;
				}
				if (targetbuf.data[pos] != ' ')
					break;
			}

			/* Locate the start of the current line in the output buffer */
			trailing_nl = strrchr(buf->data, '\n');
			if (trailing_nl == NULL)
				trailing_nl = buf->data;
			else
				trailing_nl++;

			/*
			 * If the field we're adding is the first in the list, or it
			 * already has a leading newline, don't add anything. Otherwise,
			 * add a newline, plus some indentation, if either the new field
			 * would cause an overflow or the last field used more than one
			 * line.
			 */
			if (colno > 1 &&
				leading_nl_pos == -1 &&
				((strlen(trailing_nl) + strlen(targetbuf.data) > context->wrapColumn) ||
				 last_was_multiline))
				appendContextKeyword(context, "", -PRETTYINDENT_STD,
									 PRETTYINDENT_STD, PRETTYINDENT_VAR);

			/* Remember this field's multiline status for next iteration */
			last_was_multiline =
				(strchr(targetbuf.data + leading_nl_pos + 1, '\n') != NULL);
		}

		/* Add the new field */
		appendStringInfoString(buf, targetbuf.data);
	}

#ifdef PGXC
	/*
	 * Because the empty target list can generate invalid SQL
	 * clause. Here, just fill a '*' to process a table without
	 * any columns, this statement will be sent to Datanodes
	 * and treated correctly on remote nodes.
	 */
	if (no_targetlist)
		appendStringInfo(buf, " *");
#endif
	/* clean up */
	pfree(targetbuf.data);
}

static void
get_setop_query(Node *setOp, Query *query, deparse_context *context,
				TupleDesc resultDesc)
{
	StringInfo	buf = context->buf;
	bool		need_paren;

	if (IsA(setOp, RangeTblRef))
	{
		RangeTblRef *rtr = (RangeTblRef *) setOp;
		RangeTblEntry *rte = rt_fetch(rtr->rtindex, query->rtable);
		Query	   *subquery = rte->subquery;

		Assert(subquery != NULL);
		Assert(subquery->setOperations == NULL);
		/* Need parens if WITH, ORDER BY, FOR UPDATE, or LIMIT; see gram.y */
		need_paren = (subquery->cteList ||
					  subquery->sortClause ||
					  subquery->rowMarks ||
					  subquery->limitOffset ||
					  subquery->limitCount);
		if (need_paren)
			appendStringInfoChar(buf, '(');
		get_query_def(subquery, buf, context->namespaces, resultDesc,
					  context->prettyFlags, context->wrapColumn,
					  context->indentLevel
#ifdef PGXC
					  , context->finalise_aggs, context->sortgroup_colno
#endif /* PGXC */
					  );
		if (need_paren)
			appendStringInfoChar(buf, ')');
	}
	else if (IsA(setOp, SetOperationStmt))
	{
		SetOperationStmt *op = (SetOperationStmt *) setOp;

		if (PRETTY_INDENT(context))
		{
			context->indentLevel += PRETTYINDENT_STD;
			appendStringInfoSpaces(buf, PRETTYINDENT_STD);
		}

		/*
		 * We force parens whenever nesting two SetOperationStmts. There are
		 * some cases in which parens are needed around a leaf query too, but
		 * those are more easily handled at the next level down (see code
		 * above).
		 */
		need_paren = !IsA(op->larg, RangeTblRef);

		if (need_paren)
			appendStringInfoChar(buf, '(');
		get_setop_query(op->larg, query, context, resultDesc);
		if (need_paren)
			appendStringInfoChar(buf, ')');

		if (!PRETTY_INDENT(context))
			appendStringInfoChar(buf, ' ');
		switch (op->op)
		{
			case SETOP_UNION:
				appendContextKeyword(context, "UNION ",
									 -PRETTYINDENT_STD, PRETTYINDENT_STD, 0);
				break;
			case SETOP_INTERSECT:
				appendContextKeyword(context, "INTERSECT ",
									 -PRETTYINDENT_STD, PRETTYINDENT_STD, 0);
				break;
			case SETOP_EXCEPT:
				appendContextKeyword(context, "EXCEPT ",
									 -PRETTYINDENT_STD, PRETTYINDENT_STD, 0);
				break;
			default:
				elog(ERROR, "unrecognized set op: %d",
					 (int) op->op);
		}
		if (op->all)
			appendStringInfo(buf, "ALL ");

		if (PRETTY_INDENT(context))
			appendContextKeyword(context, "", 0, 0, 0);

		need_paren = !IsA(op->rarg, RangeTblRef);

		if (need_paren)
			appendStringInfoChar(buf, '(');
		get_setop_query(op->rarg, query, context, resultDesc);
		if (need_paren)
			appendStringInfoChar(buf, ')');

		if (PRETTY_INDENT(context))
			context->indentLevel -= PRETTYINDENT_STD;
	}
	else
	{
		elog(ERROR, "unrecognized node type: %d",
			 (int) nodeTag(setOp));
	}
}

/*
 * Display a sort/group clause.
 *
 * Also returns the expression tree, so caller need not find it again.
 */
static Node *
get_rule_sortgroupclause(SortGroupClause *srt, List *tlist, bool force_colno,
						 deparse_context *context)
{
	StringInfo	buf = context->buf;
	TargetEntry *tle;
	Node	   *expr;

	tle = get_sortgroupclause_tle(srt, tlist);
	expr = (Node *) tle->expr;

	/*
	 * Use column-number form if requested by caller.  Otherwise, if
	 * expression is a constant, force it to be dumped with an explicit cast
	 * as decoration --- this is because a simple integer constant is
	 * ambiguous (and will be misinterpreted by findTargetlistEntry()) if we
	 * dump it without any decoration.	Otherwise, just dump the expression
	 * normally.
	 */
	if (force_colno || context->sortgroup_colno)
	{
		Assert(!tle->resjunk);
		appendStringInfo(buf, "%d", tle->resno);
	}
	else if (expr && IsA(expr, Const))
		get_const_expr((Const *) expr, context, 1);
	else
		get_rule_expr(expr, context, true);

	return expr;
}

/*
 * Display an ORDER BY list.
 */
static void
get_rule_orderby(List *orderList, List *targetList,
				 bool force_colno, deparse_context *context)
{
	StringInfo	buf = context->buf;
	const char *sep;
	ListCell   *l;

	sep = "";
	foreach(l, orderList)
	{
		SortGroupClause *srt = (SortGroupClause *) lfirst(l);
		Node	   *sortexpr;
		Oid			sortcoltype;
		TypeCacheEntry *typentry;

		appendStringInfoString(buf, sep);
		sortexpr = get_rule_sortgroupclause(srt, targetList,
											force_colno, context);
		sortcoltype = exprType(sortexpr);
		/* See whether operator is default < or > for datatype */
		typentry = lookup_type_cache(sortcoltype,
									 TYPECACHE_LT_OPR | TYPECACHE_GT_OPR);
		if (srt->sortop == typentry->lt_opr)
		{
			/* ASC is default, so emit nothing for it */
			if (srt->nulls_first)
				appendStringInfo(buf, " NULLS FIRST");
		}
		else if (srt->sortop == typentry->gt_opr)
		{
			appendStringInfo(buf, " DESC");
			/* DESC defaults to NULLS FIRST */
			if (!srt->nulls_first)
				appendStringInfo(buf, " NULLS LAST");
		}
		else
		{
			appendStringInfo(buf, " USING %s",
							 generate_operator_name(srt->sortop,
													sortcoltype,
													sortcoltype));
			/* be specific to eliminate ambiguity */
			if (srt->nulls_first)
				appendStringInfo(buf, " NULLS FIRST");
			else
				appendStringInfo(buf, " NULLS LAST");
		}
		sep = ", ";
	}
}

/*
 * Display a WINDOW clause.
 *
 * Note that the windowClause list might contain only anonymous window
 * specifications, in which case we should print nothing here.
 */
static void
get_rule_windowclause(Query *query, deparse_context *context)
{
	StringInfo	buf = context->buf;
	const char *sep;
	ListCell   *l;

	sep = NULL;
	foreach(l, query->windowClause)
	{
		WindowClause *wc = (WindowClause *) lfirst(l);

		if (wc->name == NULL)
			continue;			/* ignore anonymous windows */

		if (sep == NULL)
			appendContextKeyword(context, " WINDOW ",
								 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
		else
			appendStringInfoString(buf, sep);

		appendStringInfo(buf, "%s AS ", quote_identifier(wc->name));

		get_rule_windowspec(wc, query->targetList, context);

		sep = ", ";
	}
}

/*
 * Display a window definition
 */
static void
get_rule_windowspec(WindowClause *wc, List *targetList,
					deparse_context *context)
{
	StringInfo	buf = context->buf;
	bool		needspace = false;
	const char *sep;
	ListCell   *l;

	appendStringInfoChar(buf, '(');
	if (wc->refname)
	{
		appendStringInfoString(buf, quote_identifier(wc->refname));
		needspace = true;
	}
	/* partition clauses are always inherited, so only print if no refname */
	if (wc->partitionClause && !wc->refname)
	{
		if (needspace)
			appendStringInfoChar(buf, ' ');
		appendStringInfoString(buf, "PARTITION BY ");
		sep = "";
		foreach(l, wc->partitionClause)
		{
			SortGroupClause *grp = (SortGroupClause *) lfirst(l);

			appendStringInfoString(buf, sep);
			get_rule_sortgroupclause(grp, targetList,
									 false, context);
			sep = ", ";
		}
		needspace = true;
	}
	/* print ordering clause only if not inherited */
	if (wc->orderClause && !wc->copiedOrder)
	{
		if (needspace)
			appendStringInfoChar(buf, ' ');
		appendStringInfoString(buf, "ORDER BY ");
		get_rule_orderby(wc->orderClause, targetList, false, context);
		needspace = true;
	}
	/* framing clause is never inherited, so print unless it's default */
	if (wc->frameOptions & FRAMEOPTION_NONDEFAULT)
	{
		if (needspace)
			appendStringInfoChar(buf, ' ');
		if (wc->frameOptions & FRAMEOPTION_RANGE)
			appendStringInfoString(buf, "RANGE ");
		else if (wc->frameOptions & FRAMEOPTION_ROWS)
			appendStringInfoString(buf, "ROWS ");
		else
			Assert(false);
		if (wc->frameOptions & FRAMEOPTION_BETWEEN)
			appendStringInfoString(buf, "BETWEEN ");
		if (wc->frameOptions & FRAMEOPTION_START_UNBOUNDED_PRECEDING)
			appendStringInfoString(buf, "UNBOUNDED PRECEDING ");
		else if (wc->frameOptions & FRAMEOPTION_START_CURRENT_ROW)
			appendStringInfoString(buf, "CURRENT ROW ");
		else if (wc->frameOptions & FRAMEOPTION_START_VALUE)
		{
			get_rule_expr(wc->startOffset, context, false);
			if (wc->frameOptions & FRAMEOPTION_START_VALUE_PRECEDING)
				appendStringInfoString(buf, " PRECEDING ");
			else if (wc->frameOptions & FRAMEOPTION_START_VALUE_FOLLOWING)
				appendStringInfoString(buf, " FOLLOWING ");
			else
				Assert(false);
		}
		else
			Assert(false);
		if (wc->frameOptions & FRAMEOPTION_BETWEEN)
		{
			appendStringInfoString(buf, "AND ");
			if (wc->frameOptions & FRAMEOPTION_END_UNBOUNDED_FOLLOWING)
				appendStringInfoString(buf, "UNBOUNDED FOLLOWING ");
			else if (wc->frameOptions & FRAMEOPTION_END_CURRENT_ROW)
				appendStringInfoString(buf, "CURRENT ROW ");
			else if (wc->frameOptions & FRAMEOPTION_END_VALUE)
			{
				get_rule_expr(wc->endOffset, context, false);
				if (wc->frameOptions & FRAMEOPTION_END_VALUE_PRECEDING)
					appendStringInfoString(buf, " PRECEDING ");
				else if (wc->frameOptions & FRAMEOPTION_END_VALUE_FOLLOWING)
					appendStringInfoString(buf, " FOLLOWING ");
				else
					Assert(false);
			}
			else
				Assert(false);
		}
		/* we will now have a trailing space; remove it */
		buf->len--;
	}
	appendStringInfoChar(buf, ')');
}

/* ----------
 * get_insert_query_def			- Parse back an INSERT parsetree
 * ----------
 */
static void
get_insert_query_def(Query *query, deparse_context *context)
{
	StringInfo	buf = context->buf;
	RangeTblEntry *select_rte = NULL;
	RangeTblEntry *values_rte = NULL;
	RangeTblEntry *rte;
	char	   *sep;
	ListCell   *values_cell;
	ListCell   *l;
	List	   *strippedexprs;

	/* Insert the WITH clause if given */
	get_with_clause(query, context);

#ifdef PGXC
	/*
	 * In the case of "INSERT ... DEFAULT VALUES" analyzed in pgxc planner,
	 * return the sql statement directly if the table has no default values.
	 */
	if (IS_PGXC_COORDINATOR && !IsConnFromCoord() && !query->targetList)
	{
		appendStringInfo(buf, "%s", query->sql_statement);
		return;
	}

	/*
	 * select_rte and values_rte are not required by INSERT queries in XC
	 * Both these should stay null for INSERT queries to work corretly
	 * Consider an example
	 * create table tt as values(1,'One'),(2,'Two');
	 * This query uses values_rte, but we do not need them in XC
	 * because it gets broken down into two queries
	 * CREATE TABLE tt(column1 int4, column2 text)
	 * and
	 * INSERT INTO tt (column1, column2) VALUES ($1, $2)
	 * Note that the insert query does not need values_rte
	 *
	 * Now consider another example
	 * insert into tt select * from tt
	 * This query uses select_rte, but again that is not required in XC
	 * Again here the query gets broken down into two queries
	 * SELECT column1, column2 FROM ONLY tt WHERE true
	 * and
	 * INSERT INTO tt (column1, column2) VALUES ($1, $2)
	 * Note again that the insert query does not need select_rte
	 * Hence we keep both select_rte and values_rte NULL.
	 */
	if (!(IS_PGXC_COORDINATOR && !IsConnFromCoord()))
	{
#endif
	/*
	 * If it's an INSERT ... SELECT or multi-row VALUES, there will be a
	 * single RTE for the SELECT or VALUES.  Plain VALUES has neither.
	 */
	foreach(l, query->rtable)
	{
		rte = (RangeTblEntry *) lfirst(l);

		if (rte->rtekind == RTE_SUBQUERY)
		{
			if (select_rte)
				elog(ERROR, "too many subquery RTEs in INSERT");
			select_rte = rte;
		}

		if (rte->rtekind == RTE_VALUES)
		{
			if (values_rte)
				elog(ERROR, "too many values RTEs in INSERT");
			values_rte = rte;
		}
	}
#ifdef PGXC
	}
#endif
	if (select_rte && values_rte)
		elog(ERROR, "both subquery and values RTEs in INSERT");
	/*
	 * Start the query with INSERT INTO relname
	 */
	rte = rt_fetch(query->resultRelation, query->rtable);
	Assert(rte->rtekind == RTE_RELATION);

	if (PRETTY_INDENT(context))
	{
		context->indentLevel += PRETTYINDENT_STD;
		appendStringInfoChar(buf, ' ');
	}
	appendStringInfo(buf, "INSERT INTO %s ",
					 generate_relation_name(rte->relid, NIL));

	/*
	 * Add the insert-column-names list.  To handle indirection properly, we
	 * need to look for indirection nodes in the top targetlist (if it's
	 * INSERT ... SELECT or INSERT ... single VALUES), or in the first
	 * expression list of the VALUES RTE (if it's INSERT ... multi VALUES). We
	 * assume that all the expression lists will have similar indirection in
	 * the latter case.
	 */
	if (values_rte)
		values_cell = list_head((List *) linitial(values_rte->values_lists));
	else
		values_cell = NULL;
	strippedexprs = NIL;
	sep = "";
	if (query->targetList)
		appendStringInfoChar(buf, '(');
	foreach(l, query->targetList)
	{
		TargetEntry *tle = (TargetEntry *) lfirst(l);

		if (tle->resjunk)
			continue;			/* ignore junk entries */

		appendStringInfoString(buf, sep);
		sep = ", ";

		/*
		 * Put out name of target column; look in the catalogs, not at
		 * tle->resname, since resname will fail to track RENAME.
		 */
		appendStringInfoString(buf,
						quote_identifier(get_relid_attribute_name(rte->relid,
															   tle->resno)));

		/*
		 * Print any indirection needed (subfields or subscripts), and strip
		 * off the top-level nodes representing the indirection assignments.
		 */
		if (values_cell)
		{
			/* we discard the stripped expression in this case */
			processIndirection((Node *) lfirst(values_cell), context, true);
			values_cell = lnext(values_cell);
		}
		else
		{
			/* we keep a list of the stripped expressions in this case */
			strippedexprs = lappend(strippedexprs,
									processIndirection((Node *) tle->expr,
													   context, true));
		}
	}
	if (query->targetList)
		appendStringInfo(buf, ") ");

	if (select_rte)
	{
		/* Add the SELECT */
		get_query_def(select_rte->subquery, buf, NIL, NULL,
					  context->prettyFlags, context->wrapColumn,
					  context->indentLevel
#ifdef PGXC
					  , context->finalise_aggs, context->sortgroup_colno
#endif /* PGXC */
					  );
	}
	else if (values_rte)
	{
		/* Add the multi-VALUES expression lists */
		get_values_def(values_rte->values_lists, context);
	}
	else if (strippedexprs)
	{
		/* Add the single-VALUES expression list */
		appendContextKeyword(context, "VALUES (",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 2);
		get_rule_expr((Node *) strippedexprs, context, false);
		appendStringInfoChar(buf, ')');
	}
	else
	{
		/* No expressions, so it must be DEFAULT VALUES */
		appendStringInfo(buf, "DEFAULT VALUES");
	}

	/* Add RETURNING if present */
	if (query->returningList)
	{
		appendContextKeyword(context, " RETURNING",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
		get_target_list(query->returningList, context, NULL);
	}
}


/* ----------
 * get_update_query_def			- Parse back an UPDATE parsetree
 * ----------
 */
static void
get_update_query_def(Query *query, deparse_context *context)
{
	StringInfo	buf = context->buf;
	char	   *sep;
	RangeTblEntry *rte;
	ListCell   *l;

	/* Insert the WITH clause if given */
	get_with_clause(query, context);

	/*
	 * Start the query with UPDATE relname SET
	 */
	rte = rt_fetch(query->resultRelation, query->rtable);
	Assert(rte->rtekind == RTE_RELATION);
	if (PRETTY_INDENT(context))
	{
		appendStringInfoChar(buf, ' ');
		context->indentLevel += PRETTYINDENT_STD;
	}
	appendStringInfo(buf, "UPDATE %s%s",
					 only_marker(rte),
					 generate_relation_name(rte->relid, NIL));
	if (rte->alias != NULL)
		appendStringInfo(buf, " %s",
						 quote_identifier(rte->alias->aliasname));
	appendStringInfoString(buf, " SET ");

	/* Add the comma separated list of 'attname = value' */
	sep = "";
	foreach(l, query->targetList)
	{
		TargetEntry *tle = (TargetEntry *) lfirst(l);
		Node	   *expr;

		if (tle->resjunk)
			continue;			/* ignore junk entries */

		appendStringInfoString(buf, sep);
		sep = ", ";

		/*
		 * Put out name of target column; look in the catalogs, not at
		 * tle->resname, since resname will fail to track RENAME.
		 */
		appendStringInfoString(buf,
						quote_identifier(get_relid_attribute_name(rte->relid,
															   tle->resno)));

		/*
		 * Print any indirection needed (subfields or subscripts), and strip
		 * off the top-level nodes representing the indirection assignments.
		 */
		expr = processIndirection((Node *) tle->expr, context, true);

		appendStringInfo(buf, " = ");

		get_rule_expr(expr, context, false);
	}

	/* Add the FROM clause if needed */
	get_from_clause(query, " FROM ", context);

	/* Add a WHERE clause if given */
	if (query->jointree->quals != NULL)
	{
		appendContextKeyword(context, " WHERE ",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
		get_rule_expr(query->jointree->quals, context, false);
	}

	/* Add RETURNING if present */
	if (query->returningList)
	{
		appendContextKeyword(context, " RETURNING",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
		get_target_list(query->returningList, context, NULL);
	}
}


/* ----------
 * get_delete_query_def			- Parse back a DELETE parsetree
 * ----------
 */
static void
get_delete_query_def(Query *query, deparse_context *context)
{
	StringInfo	buf = context->buf;
	RangeTblEntry *rte;

	/* Insert the WITH clause if given */
	get_with_clause(query, context);

	/*
	 * Start the query with DELETE FROM relname
	 */
	rte = rt_fetch(query->resultRelation, query->rtable);
	Assert(rte->rtekind == RTE_RELATION);
	if (PRETTY_INDENT(context))
	{
		appendStringInfoChar(buf, ' ');
		context->indentLevel += PRETTYINDENT_STD;
	}
	appendStringInfo(buf, "DELETE FROM %s%s",
					 only_marker(rte),
					 generate_relation_name(rte->relid, NIL));
	if (rte->alias != NULL)
		appendStringInfo(buf, " %s",
						 quote_identifier(rte->alias->aliasname));

	/* Add the USING clause if given */
	get_from_clause(query, " USING ", context);

	/* Add a WHERE clause if given */
	if (query->jointree->quals != NULL)
	{
		appendContextKeyword(context, " WHERE ",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
		get_rule_expr(query->jointree->quals, context, false);
	}

	/* Add RETURNING if present */
	if (query->returningList)
	{
		appendContextKeyword(context, " RETURNING",
							 -PRETTYINDENT_STD, PRETTYINDENT_STD, 1);
		get_target_list(query->returningList, context, NULL);
	}
}


/* ----------
 * get_utility_query_def			- Parse back a UTILITY parsetree
 * ----------
 */
static void
get_utility_query_def(Query *query, deparse_context *context)
{
	StringInfo	buf = context->buf;

	if (query->utilityStmt && IsA(query->utilityStmt, NotifyStmt))
	{
		NotifyStmt *stmt = (NotifyStmt *) query->utilityStmt;

		appendContextKeyword(context, "",
							 0, PRETTYINDENT_STD, 1);
		appendStringInfo(buf, "NOTIFY %s",
						 quote_identifier(stmt->conditionname));
		if (stmt->payload)
		{
			appendStringInfoString(buf, ", ");
			simple_quote_literal(buf, stmt->payload);
		}
	}
#ifdef PGXC
	else if (query->utilityStmt && IsA(query->utilityStmt, CreateStmt))
	{
		CreateStmt *stmt = (CreateStmt *) query->utilityStmt;
		ListCell   *column;
		const char *delimiter = "";
		RangeVar   *relation = stmt->relation;
		bool		istemp = (relation->relpersistence == RELPERSISTENCE_TEMP);
		bool		isunlogged = (relation->relpersistence == RELPERSISTENCE_UNLOGGED);

		if (istemp && relation->schemaname)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
					 errmsg("temporary tables cannot specify a schema name")));

		appendStringInfo(buf, "CREATE %s %s TABLE ",
				istemp ? "TEMP" : "",
				isunlogged ? "UNLOGGED" : "");

		if (relation->schemaname && relation->schemaname[0])
			appendStringInfo(buf, "%s.", relation->schemaname);
		appendStringInfo(buf, "%s", relation->relname);

		appendStringInfo(buf, "(");
		foreach(column, stmt->tableElts)
		{
			Node *node = (Node *) lfirst(column);

			appendStringInfo(buf, "%s", delimiter);
			delimiter = ", ";

			if (IsA(node, ColumnDef))
			{
				ColumnDef *coldef = (ColumnDef *) node;
				TypeName *typename = coldef->typeName;
				Type type;

				/* error out if we have no recourse at all */
				if (!OidIsValid(typename->typeOid))
					ereport(ERROR,
							(errcode(ERRCODE_SYNTAX_ERROR),
							 errmsg("improper type oid: \"%u\"", typename->typeOid)));

				/* get typename from the oid */
				type = typeidType(typename->typeOid);

				if (!HeapTupleIsValid(type))
					ereport(ERROR,
							(errcode(ERRCODE_UNDEFINED_OBJECT),
							 errmsg("type \"%u\" does not exist",
								 typename->typeOid)));
				appendStringInfo(buf, "%s %s", quote_identifier(coldef->colname),
						typeTypeName(type));
				ReleaseSysCache(type);
			}
			else
				elog(ERROR, "Invalid table column definition.");
		}
		appendStringInfo(buf, ")");

		/* Append storage parameters, like for instance WITH (OIDS) */
		if (list_length(stmt->options) > 0)
		{
			Datum        reloptions;
			static char *validnsps[] = HEAP_RELOPT_NAMESPACES;

			reloptions = transformRelOptions((Datum) 0, stmt->options, NULL, validnsps,
										 false, false);

			if (reloptions)
			{
				Datum   sep, txt;
				/* Below is inspired from flatten_reloptions() */
				sep = CStringGetTextDatum(", ");
				txt = OidFunctionCall2(F_ARRAY_TO_TEXT, reloptions, sep);
				appendStringInfo(buf, " WITH (%s)", TextDatumGetCString(txt));
			}
		}

		/* add the on commit clauses for temporary tables */
		switch (stmt->oncommit)
		{
			case ONCOMMIT_NOOP:
				/* do nothing */
				break;

			case ONCOMMIT_PRESERVE_ROWS:
				appendStringInfo(buf, " ON COMMIT PRESERVE ROWS");
				break;

			case ONCOMMIT_DELETE_ROWS:
				appendStringInfo(buf, " ON COMMIT DELETE ROWS");
				break;

			case ONCOMMIT_DROP:
				appendStringInfo(buf, " ON COMMIT DROP");
				break;
		}

		if (stmt->distributeby)
		{
			/* add the on commit clauses for temporary tables */
			switch (stmt->distributeby->disttype)
			{
				case DISTTYPE_REPLICATION:
					appendStringInfo(buf, " DISTRIBUTE BY REPLICATION");
					break;

				case DISTTYPE_HASH:
					appendStringInfo(buf, " DISTRIBUTE BY HASH(%s)", stmt->distributeby->colname);
					break;

				case DISTTYPE_ROUNDROBIN:
					appendStringInfo(buf, " DISTRIBUTE BY ROUNDROBIN");
					break;

				case DISTTYPE_MODULO:
					appendStringInfo(buf, " DISTRIBUTE BY MODULO(%s)", stmt->distributeby->colname);
					break;

				default:
					ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR),
								errmsg("Invalid distribution type")));

			}
		}

		if (stmt->subcluster)
		{
			ListCell   *cell;

			switch (stmt->subcluster->clustertype)
			{
				case SUBCLUSTER_NODE:
					appendStringInfo(buf, " TO NODE (");

					/* Add node members */
					Assert(stmt->subcluster->members);
					foreach(cell, stmt->subcluster->members)
					{
						appendStringInfo(buf, " %s", strVal(lfirst(cell)));
						if (cell->next)
							appendStringInfo(buf, ",");
					}
					appendStringInfo(buf, ")");
					break;

				case SUBCLUSTER_GROUP:
					appendStringInfo(buf, " TO GROUP");

					/* Add group members */
					Assert(stmt->subcluster->members);
					foreach(cell, stmt->subcluster->members)
					{
						appendStringInfo(buf, " %s", strVal(lfirst(cell)));
						if (cell->next)
							appendStringInfo(buf, ",");
					}
					break;

				case SUBCLUSTER_NONE:
				default:
					/* Nothing to do */
					break;
			}
		}
	}
#endif
	else
	{
		/* Currently only NOTIFY utility commands can appear in rules */
		elog(ERROR, "unexpected utility statement type");
	}
}


/*
 * Display a Var appropriately.
 *
 * In some cases (currently only when recursing into an unnamed join)
 * the Var's varlevelsup has to be interpreted with respect to a context
 * above the current one; levelsup indicates the offset.
 *
 * If istoplevel is TRUE, the Var is at the top level of a SELECT's
 * targetlist, which means we need special treatment of whole-row Vars.
 * Instead of the normal "tab.*", we'll print "tab.*::typename", which is a
 * dirty hack to prevent "tab.*" from being expanded into multiple columns.
 * (The parser will strip the useless coercion, so no inefficiency is added in
 * dump and reload.)  We used to print just "tab" in such cases, but that is
 * ambiguous and will yield the wrong result if "tab" is also a plain column
 * name in the query.
 *
 * Returns the attname of the Var, or NULL if the Var has no attname (because
 * it is a whole-row Var).
 */
static char *
get_variable(Var *var, int levelsup, bool istoplevel, deparse_context *context)
{
	StringInfo	buf = context->buf;
	RangeTblEntry *rte;
	AttrNumber	attnum;
	int			netlevelsup;
	deparse_namespace *dpns;
	char	   *schemaname;
	char	   *refname;
	char	   *attname;

	/* Find appropriate nesting depth */
	netlevelsup = var->varlevelsup + levelsup;
	if (netlevelsup >= list_length(context->namespaces))
		elog(ERROR, "bogus varlevelsup: %d offset %d",
			 var->varlevelsup, levelsup);
	dpns = (deparse_namespace *) list_nth(context->namespaces,
										  netlevelsup);

	/*
	 * Try to find the relevant RTE in this rtable.  In a plan tree, it's
	 * likely that varno is OUTER_VAR or INNER_VAR, in which case we must dig
	 * down into the subplans, or INDEX_VAR, which is resolved similarly.
	 */
#ifdef PGXC
	if (dpns->remotequery)
	{
		rte = rt_fetch(1, dpns->rtable);
		attnum = var->varattno;
	}
	else
#endif
	if (var->varno >= 1 && var->varno <= list_length(dpns->rtable))
	{
		rte = rt_fetch(var->varno, dpns->rtable);
		attnum = var->varattno;
	}
	else if (var->varno == OUTER_VAR && dpns->outer_tlist)
	{
		TargetEntry *tle;
		deparse_namespace save_dpns;

		tle = get_tle_by_resno(dpns->outer_tlist, var->varattno);
		if (!tle)
			elog(ERROR, "bogus varattno for OUTER_VAR var: %d", var->varattno);

		Assert(netlevelsup == 0);
		push_child_plan(dpns, dpns->outer_planstate, &save_dpns);

		/*
		 * Force parentheses because our caller probably assumed a Var is a
		 * simple expression.
		 */
		if (!IsA(tle->expr, Var))
			appendStringInfoChar(buf, '(');
		get_rule_expr((Node *) tle->expr, context, true);
		if (!IsA(tle->expr, Var))
			appendStringInfoChar(buf, ')');

		pop_child_plan(dpns, &save_dpns);
		return NULL;
	}
	else if (var->varno == INNER_VAR && dpns->inner_tlist)
	{
		TargetEntry *tle;
		deparse_namespace save_dpns;

		tle = get_tle_by_resno(dpns->inner_tlist, var->varattno);
		if (!tle)
			elog(ERROR, "bogus varattno for INNER_VAR var: %d", var->varattno);

		Assert(netlevelsup == 0);
		push_child_plan(dpns, dpns->inner_planstate, &save_dpns);

		/*
		 * Force parentheses because our caller probably assumed a Var is a
		 * simple expression.
		 */
		if (!IsA(tle->expr, Var))
			appendStringInfoChar(buf, '(');
		get_rule_expr((Node *) tle->expr, context, true);
		if (!IsA(tle->expr, Var))
			appendStringInfoChar(buf, ')');

		pop_child_plan(dpns, &save_dpns);
		return NULL;
	}
	else if (var->varno == INDEX_VAR && dpns->index_tlist)
	{
		TargetEntry *tle;

		tle = get_tle_by_resno(dpns->index_tlist, var->varattno);
		if (!tle)
			elog(ERROR, "bogus varattno for INDEX_VAR var: %d", var->varattno);

		Assert(netlevelsup == 0);

		/*
		 * Force parentheses because our caller probably assumed a Var is a
		 * simple expression.
		 */
		if (!IsA(tle->expr, Var))
			appendStringInfoChar(buf, '(');
		get_rule_expr((Node *) tle->expr, context, true);
		if (!IsA(tle->expr, Var))
			appendStringInfoChar(buf, ')');

		return NULL;
	}
	else
	{
		elog(ERROR, "bogus varno: %d", var->varno);
		return NULL;			/* keep compiler quiet */
	}

	/*
	 * The planner will sometimes emit Vars referencing resjunk elements of a
	 * subquery's target list (this is currently only possible if it chooses
	 * to generate a "physical tlist" for a SubqueryScan or CteScan node).
	 * Although we prefer to print subquery-referencing Vars using the
	 * subquery's alias, that's not possible for resjunk items since they have
	 * no alias.  So in that case, drill down to the subplan and print the
	 * contents of the referenced tlist item.  This works because in a plan
	 * tree, such Vars can only occur in a SubqueryScan or CteScan node, and
	 * we'll have set dpns->inner_planstate to reference the child plan node.
	 */
	if ((rte->rtekind == RTE_SUBQUERY || rte->rtekind == RTE_CTE) &&
		attnum > list_length(rte->eref->colnames) &&
		dpns->inner_planstate)
	{
		TargetEntry *tle;
		deparse_namespace save_dpns;

		tle = get_tle_by_resno(dpns->inner_tlist, var->varattno);
		if (!tle)
			elog(ERROR, "bogus varattno for subquery var: %d", var->varattno);

		Assert(netlevelsup == 0);
		push_child_plan(dpns, dpns->inner_planstate, &save_dpns);

		/*
		 * Force parentheses because our caller probably assumed a Var is a
		 * simple expression.
		 */
		if (!IsA(tle->expr, Var))
			appendStringInfoChar(buf, '(');
		get_rule_expr((Node *) tle->expr, context, true);
		if (!IsA(tle->expr, Var))
			appendStringInfoChar(buf, ')');

		pop_child_plan(dpns, &save_dpns);
		return NULL;
	}

#ifdef PGXC
	if (rte->rtekind == RTE_REMOTE_DUMMY &&
		attnum > list_length(rte->eref->colnames) &&
		dpns->planstate)
	{
		TargetEntry *tle;
		RemoteQuery *rqplan;
		Assert(IsA(dpns->planstate, RemoteQueryState));
		Assert(netlevelsup == 0);

		/*
		 * Get the expression representing the given Var from base_tlist of the
		 * RemoteQuery
		 */
		rqplan = (RemoteQuery *)dpns->planstate->plan;
		Assert(IsA(rqplan, RemoteQuery));
		tle = get_tle_by_resno(rqplan->base_tlist, var->varattno);
		if (!tle)
			elog(ERROR, "bogus varattno for remotequery var: %d", var->varattno);
		/*
		 * Force parentheses because our caller probably assumed a Var is a
		 * simple expression.
		 */
		if (!IsA(tle->expr, Var))
			appendStringInfoChar(buf, '(');
		get_rule_expr((Node *) tle->expr, context, true);
		if (!IsA(tle->expr, Var))
			appendStringInfoChar(buf, ')');

		return NULL;
	}
#endif /* PGXC */

	/* Identify names to use */
	schemaname = NULL;			/* default assumptions */
	refname = rte->eref->aliasname;

	/* Exceptions occur only if the RTE is alias-less */
	if (rte->alias == NULL)
	{
		if (rte->rtekind == RTE_RELATION)
		{
			/*
			 * It's possible that use of the bare refname would find another
			 * more-closely-nested RTE, or be ambiguous, in which case we need
			 * to specify the schemaname to avoid these errors.
			 */
			if (find_rte_by_refname(rte->eref->aliasname, context) != rte)
				schemaname = get_namespace_name(get_rel_namespace(rte->relid));
		}
		else if (rte->rtekind == RTE_JOIN)
		{
			/*
			 * If it's an unnamed join, look at the expansion of the alias
			 * variable.  If it's a simple reference to one of the input vars
			 * then recursively print the name of that var, instead. (This
			 * allows correct decompiling of cases where there are identically
			 * named columns on both sides of the join.) When it's not a
			 * simple reference, we have to just print the unqualified
			 * variable name (this can only happen with columns that were
			 * merged by USING or NATURAL clauses).
			 *
			 * This wouldn't work in decompiling plan trees, because we don't
			 * store joinaliasvars lists after planning; but a plan tree
			 * should never contain a join alias variable.
			 */
			if (rte->joinaliasvars == NIL)
				elog(ERROR, "cannot decompile join alias var in plan tree");
			if (attnum > 0)
			{
				Var		   *aliasvar;

				aliasvar = (Var *) list_nth(rte->joinaliasvars, attnum - 1);
				if (IsA(aliasvar, Var))
				{
					return get_variable(aliasvar, var->varlevelsup + levelsup,
										istoplevel, context);
				}
			}

			/*
			 * Unnamed join has neither schemaname nor refname.  (Note: since
			 * it's unnamed, there is no way the user could have referenced it
			 * to create a whole-row Var for it.  So we don't have to cover
			 * that case below.)
			 */
			refname = NULL;
		}
	}

	if (attnum == InvalidAttrNumber)
		attname = NULL;
	else
		attname = get_rte_attribute_name(rte, attnum);

	if (refname && (context->varprefix || attname == NULL))
	{
		if (schemaname)
			appendStringInfo(buf, "%s.",
							 quote_identifier(schemaname));
		appendStringInfoString(buf, quote_identifier(refname));
		appendStringInfoChar(buf, '.');
	}
	if (attname)
		appendStringInfoString(buf, quote_identifier(attname));
	else
	{
		appendStringInfoChar(buf, '*');
		if (istoplevel)
			appendStringInfo(buf, "::%s",
							 format_type_with_typemod(var->vartype,
													  var->vartypmod));
	}

	return attname;
}


/*
 * Get the name of a field of an expression of composite type.	The
 * expression is usually a Var, but we handle other cases too.
 *
 * levelsup is an extra offset to interpret the Var's varlevelsup correctly.
 *
 * This is fairly straightforward when the expression has a named composite
 * type; we need only look up the type in the catalogs.  However, the type
 * could also be RECORD.  Since no actual table or view column is allowed to
 * have type RECORD, a Var of type RECORD must refer to a JOIN or FUNCTION RTE
 * or to a subquery output.  We drill down to find the ultimate defining
 * expression and attempt to infer the field name from it.	We ereport if we
 * can't determine the name.
 *
 * Similarly, a PARAM of type RECORD has to refer to some expression of
 * a determinable composite type.
 */
static const char *
get_name_for_var_field(Var *var, int fieldno,
					   int levelsup, deparse_context *context)
{
	RangeTblEntry *rte;
	AttrNumber	attnum;
	int			netlevelsup;
	deparse_namespace *dpns;
	TupleDesc	tupleDesc;
	Node	   *expr;

	/*
	 * If it's a RowExpr that was expanded from a whole-row Var, use the
	 * column names attached to it.
	 */
	if (IsA(var, RowExpr))
	{
		RowExpr    *r = (RowExpr *) var;

		if (fieldno > 0 && fieldno <= list_length(r->colnames))
			return strVal(list_nth(r->colnames, fieldno - 1));
	}

	/*
	 * If it's a Param of type RECORD, try to find what the Param refers to.
	 */
	if (IsA(var, Param))
	{
		Param	   *param = (Param *) var;
		ListCell   *ancestor_cell;

		expr = find_param_referent(param, context, &dpns, &ancestor_cell);
		if (expr)
		{
			/* Found a match, so recurse to decipher the field name */
			deparse_namespace save_dpns;
			const char *result;

			push_ancestor_plan(dpns, ancestor_cell, &save_dpns);
			result = get_name_for_var_field((Var *) expr, fieldno,
											0, context);
			pop_ancestor_plan(dpns, &save_dpns);
			return result;
		}
	}

	/*
	 * If it's a Var of type RECORD, we have to find what the Var refers to;
	 * if not, we can use get_expr_result_type. If that fails, we try
	 * lookup_rowtype_tupdesc, which will probably fail too, but will ereport
	 * an acceptable message.
	 */
	if (!IsA(var, Var) ||
		var->vartype != RECORDOID)
	{
		if (get_expr_result_type((Node *) var, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
			tupleDesc = lookup_rowtype_tupdesc_copy(exprType((Node *) var),
													exprTypmod((Node *) var));
		Assert(tupleDesc);
		/* Got the tupdesc, so we can extract the field name */
		Assert(fieldno >= 1 && fieldno <= tupleDesc->natts);
		return NameStr(tupleDesc->attrs[fieldno - 1]->attname);
	}

	/* Find appropriate nesting depth */
	netlevelsup = var->varlevelsup + levelsup;
	if (netlevelsup >= list_length(context->namespaces))
		elog(ERROR, "bogus varlevelsup: %d offset %d",
			 var->varlevelsup, levelsup);
	dpns = (deparse_namespace *) list_nth(context->namespaces,
										  netlevelsup);

	/*
	 * Try to find the relevant RTE in this rtable.  In a plan tree, it's
	 * likely that varno is OUTER_VAR or INNER_VAR, in which case we must dig
	 * down into the subplans, or INDEX_VAR, which is resolved similarly.
	 */
	if (var->varno >= 1 && var->varno <= list_length(dpns->rtable))
	{
		rte = rt_fetch(var->varno, dpns->rtable);
		attnum = var->varattno;
	}
	else if (var->varno == OUTER_VAR && dpns->outer_tlist)
	{
		TargetEntry *tle;
		deparse_namespace save_dpns;
		const char *result;

		tle = get_tle_by_resno(dpns->outer_tlist, var->varattno);
		if (!tle)
			elog(ERROR, "bogus varattno for OUTER_VAR var: %d", var->varattno);

		Assert(netlevelsup == 0);
		push_child_plan(dpns, dpns->outer_planstate, &save_dpns);

		result = get_name_for_var_field((Var *) tle->expr, fieldno,
										levelsup, context);

		pop_child_plan(dpns, &save_dpns);
		return result;
	}
	else if (var->varno == INNER_VAR && dpns->inner_tlist)
	{
		TargetEntry *tle;
		deparse_namespace save_dpns;
		const char *result;

		tle = get_tle_by_resno(dpns->inner_tlist, var->varattno);
		if (!tle)
			elog(ERROR, "bogus varattno for INNER_VAR var: %d", var->varattno);

		Assert(netlevelsup == 0);
		push_child_plan(dpns, dpns->inner_planstate, &save_dpns);

		result = get_name_for_var_field((Var *) tle->expr, fieldno,
										levelsup, context);

		pop_child_plan(dpns, &save_dpns);
		return result;
	}
	else if (var->varno == INDEX_VAR && dpns->index_tlist)
	{
		TargetEntry *tle;
		const char *result;

		tle = get_tle_by_resno(dpns->index_tlist, var->varattno);
		if (!tle)
			elog(ERROR, "bogus varattno for INDEX_VAR var: %d", var->varattno);

		Assert(netlevelsup == 0);

		result = get_name_for_var_field((Var *) tle->expr, fieldno,
										levelsup, context);

		return result;
	}
	else
	{
		elog(ERROR, "bogus varno: %d", var->varno);
		return NULL;			/* keep compiler quiet */
	}

	if (attnum == InvalidAttrNumber)
	{
		/* Var is whole-row reference to RTE, so select the right field */
		return get_rte_attribute_name(rte, fieldno);
	}

	/*
	 * This part has essentially the same logic as the parser's
	 * expandRecordVariable() function, but we are dealing with a different
	 * representation of the input context, and we only need one field name
	 * not a TupleDesc.  Also, we need special cases for finding subquery and
	 * CTE subplans when deparsing Plan trees.
	 */
	expr = (Node *) var;		/* default if we can't drill down */

	switch (rte->rtekind)
	{
		case RTE_RELATION:
		case RTE_VALUES:

			/*
			 * This case should not occur: a column of a table or values list
			 * shouldn't have type RECORD.  Fall through and fail (most
			 * likely) at the bottom.
			 */
			break;
		case RTE_SUBQUERY:
			/* Subselect-in-FROM: examine sub-select's output expr */
			{
				if (rte->subquery)
				{
					TargetEntry *ste = get_tle_by_resno(rte->subquery->targetList,
														attnum);

					if (ste == NULL || ste->resjunk)
						elog(ERROR, "subquery %s does not have attribute %d",
							 rte->eref->aliasname, attnum);
					expr = (Node *) ste->expr;
					if (IsA(expr, Var))
					{
						/*
						 * Recurse into the sub-select to see what its Var
						 * refers to. We have to build an additional level of
						 * namespace to keep in step with varlevelsup in the
						 * subselect.
						 */
						deparse_namespace mydpns;
						const char *result;

						memset(&mydpns, 0, sizeof(mydpns));
						mydpns.rtable = rte->subquery->rtable;
						mydpns.ctes = rte->subquery->cteList;
#ifdef PGXC
						mydpns.remotequery = false;
#endif

						context->namespaces = lcons(&mydpns,
													context->namespaces);

						result = get_name_for_var_field((Var *) expr, fieldno,
														0, context);

						context->namespaces =
							list_delete_first(context->namespaces);

						return result;
					}
					/* else fall through to inspect the expression */
				}
				else
				{
					/*
					 * We're deparsing a Plan tree so we don't have complete
					 * RTE entries (in particular, rte->subquery is NULL). But
					 * the only place we'd see a Var directly referencing a
					 * SUBQUERY RTE is in a SubqueryScan plan node, and we can
					 * look into the child plan's tlist instead.
					 */
					TargetEntry *tle;
					deparse_namespace save_dpns;
					const char *result;

					if (!dpns->inner_planstate)
						elog(ERROR, "failed to find plan for subquery %s",
							 rte->eref->aliasname);
					tle = get_tle_by_resno(dpns->inner_tlist, attnum);
					if (!tle)
						elog(ERROR, "bogus varattno for subquery var: %d",
							 attnum);
					Assert(netlevelsup == 0);
					push_child_plan(dpns, dpns->inner_planstate, &save_dpns);

					result = get_name_for_var_field((Var *) tle->expr, fieldno,
													levelsup, context);

					pop_child_plan(dpns, &save_dpns);
					return result;
				}
			}
			break;
		case RTE_JOIN:
			/* Join RTE --- recursively inspect the alias variable */
			if (rte->joinaliasvars == NIL)
				elog(ERROR, "cannot decompile join alias var in plan tree");
			Assert(attnum > 0 && attnum <= list_length(rte->joinaliasvars));
			expr = (Node *) list_nth(rte->joinaliasvars, attnum - 1);
			if (IsA(expr, Var))
				return get_name_for_var_field((Var *) expr, fieldno,
											  var->varlevelsup + levelsup,
											  context);
			/* else fall through to inspect the expression */
			break;
		case RTE_FUNCTION:

			/*
			 * We couldn't get here unless a function is declared with one of
			 * its result columns as RECORD, which is not allowed.
			 */
			break;
		case RTE_CTE:
			/* CTE reference: examine subquery's output expr */
			{
				CommonTableExpr *cte = NULL;
				Index		ctelevelsup;
				ListCell   *lc;

				/*
				 * Try to find the referenced CTE using the namespace stack.
				 */
				ctelevelsup = rte->ctelevelsup + netlevelsup;
				if (ctelevelsup >= list_length(context->namespaces))
					lc = NULL;
				else
				{
					deparse_namespace *ctedpns;

					ctedpns = (deparse_namespace *)
						list_nth(context->namespaces, ctelevelsup);
					foreach(lc, ctedpns->ctes)
					{
						cte = (CommonTableExpr *) lfirst(lc);
						if (strcmp(cte->ctename, rte->ctename) == 0)
							break;
					}
				}
				if (lc != NULL)
				{
					Query	   *ctequery = (Query *) cte->ctequery;
					TargetEntry *ste = get_tle_by_resno(GetCTETargetList(cte),
														attnum);

					if (ste == NULL || ste->resjunk)
						elog(ERROR, "subquery %s does not have attribute %d",
							 rte->eref->aliasname, attnum);
					expr = (Node *) ste->expr;
					if (IsA(expr, Var))
					{
						/*
						 * Recurse into the CTE to see what its Var refers to.
						 * We have to build an additional level of namespace
						 * to keep in step with varlevelsup in the CTE.
						 * Furthermore it could be an outer CTE, so we may
						 * have to delete some levels of namespace.
						 */
						List	   *save_nslist = context->namespaces;
						List	   *new_nslist;
						deparse_namespace mydpns;
						const char *result;

						memset(&mydpns, 0, sizeof(mydpns));
						mydpns.rtable = ctequery->rtable;
						mydpns.ctes = ctequery->cteList;
#ifdef PGXC
						mydpns.remotequery = false;
#endif

						new_nslist = list_copy_tail(context->namespaces,
													ctelevelsup);
						context->namespaces = lcons(&mydpns, new_nslist);

						result = get_name_for_var_field((Var *) expr, fieldno,
														0, context);

						context->namespaces = save_nslist;

						return result;
					}
					/* else fall through to inspect the expression */
				}
				else
				{
					/*
					 * We're deparsing a Plan tree so we don't have a CTE
					 * list.  But the only place we'd see a Var directly
					 * referencing a CTE RTE is in a CteScan plan node, and we
					 * can look into the subplan's tlist instead.
					 */
					TargetEntry *tle;
					deparse_namespace save_dpns;
					const char *result;

					if (!dpns->inner_planstate)
						elog(ERROR, "failed to find plan for CTE %s",
							 rte->eref->aliasname);
					tle = get_tle_by_resno(dpns->inner_tlist, attnum);
					if (!tle)
						elog(ERROR, "bogus varattno for subquery var: %d",
							 attnum);
					Assert(netlevelsup == 0);
					push_child_plan(dpns, dpns->inner_planstate, &save_dpns);

					result = get_name_for_var_field((Var *) tle->expr, fieldno,
													levelsup, context);

					pop_child_plan(dpns, &save_dpns);
					return result;
				}
			}
			break;
#ifdef PGXC
		case RTE_REMOTE_DUMMY:
			elog(ERROR, "Invalid RTE found");
			break;
#endif /* PGXC */
	}

	/*
	 * We now have an expression we can't expand any more, so see if
	 * get_expr_result_type() can do anything with it.	If not, pass to
	 * lookup_rowtype_tupdesc() which will probably fail, but will give an
	 * appropriate error message while failing.
	 */
	if (get_expr_result_type(expr, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
		tupleDesc = lookup_rowtype_tupdesc_copy(exprType(expr),
												exprTypmod(expr));
	Assert(tupleDesc);
	/* Got the tupdesc, so we can extract the field name */
	Assert(fieldno >= 1 && fieldno <= tupleDesc->natts);
	return NameStr(tupleDesc->attrs[fieldno - 1]->attname);
}


/*
 * find_rte_by_refname		- look up an RTE by refname in a deparse context
 *
 * Returns NULL if there is no matching RTE or the refname is ambiguous.
 *
 * NOTE: this code is not really correct since it does not take account of
 * the fact that not all the RTEs in a rangetable may be visible from the
 * point where a Var reference appears.  For the purposes we need, however,
 * the only consequence of a false match is that we might stick a schema
 * qualifier on a Var that doesn't really need it.  So it seems close
 * enough.
 */
static RangeTblEntry *
find_rte_by_refname(const char *refname, deparse_context *context)
{
	RangeTblEntry *result = NULL;
	ListCell   *nslist;

	foreach(nslist, context->namespaces)
	{
		deparse_namespace *dpns = (deparse_namespace *) lfirst(nslist);
		ListCell   *rtlist;

		foreach(rtlist, dpns->rtable)
		{
			RangeTblEntry *rte = (RangeTblEntry *) lfirst(rtlist);

			if (strcmp(rte->eref->aliasname, refname) == 0)
			{
				if (result)
					return NULL;	/* it's ambiguous */
				result = rte;
			}
		}
		if (result)
			break;
	}
	return result;
}

/*
 * Try to find the referenced expression for a PARAM_EXEC Param that might
 * reference a parameter supplied by an upper NestLoop or SubPlan plan node.
 *
 * If successful, return the expression and set *dpns_p and *ancestor_cell_p
 * appropriately for calling push_ancestor_plan().	If no referent can be
 * found, return NULL.
 */
static Node *
find_param_referent(Param *param, deparse_context *context,
					deparse_namespace **dpns_p, ListCell **ancestor_cell_p)
{
	/* Initialize output parameters to prevent compiler warnings */
	*dpns_p = NULL;
	*ancestor_cell_p = NULL;

	/*
	 * If it's a PARAM_EXEC parameter, look for a matching NestLoopParam or
	 * SubPlan argument.  This will necessarily be in some ancestor of the
	 * current expression's PlanState.
	 */
	if (param->paramkind == PARAM_EXEC)
	{
		deparse_namespace *dpns;
		PlanState  *child_ps;
		bool		in_same_plan_level;
		ListCell   *lc;

		dpns = (deparse_namespace *) linitial(context->namespaces);
		child_ps = dpns->planstate;
		in_same_plan_level = true;

		foreach(lc, dpns->ancestors)
		{
			PlanState  *ps = (PlanState *) lfirst(lc);
			ListCell   *lc2;

			/*
			 * NestLoops transmit params to their inner child only; also, once
			 * we've crawled up out of a subplan, this couldn't possibly be
			 * the right match.
			 */
			if (IsA(ps, NestLoopState) &&
				child_ps == innerPlanState(ps) &&
				in_same_plan_level)
			{
				NestLoop   *nl = (NestLoop *) ps->plan;

				foreach(lc2, nl->nestParams)
				{
					NestLoopParam *nlp = (NestLoopParam *) lfirst(lc2);

					if (nlp->paramno == param->paramid)
					{
						/* Found a match, so return it */
						*dpns_p = dpns;
						*ancestor_cell_p = lc;
						return (Node *) nlp->paramval;
					}
				}
			}

			/*
			 * Check to see if we're crawling up from a subplan.
			 */
			foreach(lc2, ps->subPlan)
			{
				SubPlanState *sstate = (SubPlanState *) lfirst(lc2);
				SubPlan    *subplan = (SubPlan *) sstate->xprstate.expr;
				ListCell   *lc3;
				ListCell   *lc4;

				if (child_ps != sstate->planstate)
					continue;

				/* Matched subplan, so check its arguments */
				forboth(lc3, subplan->parParam, lc4, subplan->args)
				{
					int			paramid = lfirst_int(lc3);
					Node	   *arg = (Node *) lfirst(lc4);

					if (paramid == param->paramid)
					{
						/* Found a match, so return it */
						*dpns_p = dpns;
						*ancestor_cell_p = lc;
						return arg;
					}
				}

				/* Keep looking, but we are emerging from a subplan. */
				in_same_plan_level = false;
				break;
			}

			/*
			 * Likewise check to see if we're emerging from an initplan.
			 * Initplans never have any parParams, so no need to search that
			 * list, but we need to know if we should reset
			 * in_same_plan_level.
			 */
			foreach(lc2, ps->initPlan)
			{
				SubPlanState *sstate = (SubPlanState *) lfirst(lc2);

				if (child_ps != sstate->planstate)
					continue;

				/* No parameters to be had here. */
				Assert(((SubPlan *) sstate->xprstate.expr)->parParam == NIL);

				/* Keep looking, but we are emerging from an initplan. */
				in_same_plan_level = false;
				break;
			}

			/* No luck, crawl up to next ancestor */
			child_ps = ps;
		}
	}

	/* No referent found */
	return NULL;
}

/*
 * Display a Param appropriately.
 */
static void
get_parameter(Param *param, deparse_context *context)
{
	Node	   *expr;
	deparse_namespace *dpns;
	ListCell   *ancestor_cell;

	/*
	 * If it's a PARAM_EXEC parameter, try to locate the expression from which
	 * the parameter was computed.	Note that failing to find a referent isn't
	 * an error, since the Param might well be a subplan output rather than an
	 * input.
	 */
	expr = find_param_referent(param, context, &dpns, &ancestor_cell);
	if (expr)
	{
		/* Found a match, so print it */
		deparse_namespace save_dpns;
		bool		save_varprefix;
		bool		need_paren;

		/* Switch attention to the ancestor plan node */
		push_ancestor_plan(dpns, ancestor_cell, &save_dpns);

		/*
		 * Force prefixing of Vars, since they won't belong to the relation
		 * being scanned in the original plan node.
		 */
		save_varprefix = context->varprefix;
		context->varprefix = true;

		/*
		 * A Param's expansion is typically a Var, Aggref, or upper-level
		 * Param, which wouldn't need extra parentheses.  Otherwise, insert
		 * parens to ensure the expression looks atomic.
		 */
		need_paren = !(IsA(expr, Var) ||
					   IsA(expr, Aggref) ||
					   IsA(expr, Param));
		if (need_paren)
			appendStringInfoChar(context->buf, '(');

		get_rule_expr(expr, context, false);

		if (need_paren)
			appendStringInfoChar(context->buf, ')');

		context->varprefix = save_varprefix;

		pop_ancestor_plan(dpns, &save_dpns);

		return;
	}

	/*
	 * Not PARAM_EXEC, or couldn't find referent: just print $N.
	 */
	appendStringInfo(context->buf, "$%d", param->paramid);
}

/*
 * get_simple_binary_op_name
 *
 * helper function for isSimpleNode
 * will return single char binary operator name, or NULL if it's not
 */
static const char *
get_simple_binary_op_name(OpExpr *expr)
{
	List	   *args = expr->args;

	if (list_length(args) == 2)
	{
		/* binary operator */
		Node	   *arg1 = (Node *) linitial(args);
		Node	   *arg2 = (Node *) lsecond(args);
		const char *op;

		op = generate_operator_name(expr->opno, exprType(arg1), exprType(arg2));
		if (strlen(op) == 1)
			return op;
	}
	return NULL;
}


/*
 * isSimpleNode - check if given node is simple (doesn't need parenthesizing)
 *
 *	true   : simple in the context of parent node's type
 *	false  : not simple
 */
static bool
isSimpleNode(Node *node, Node *parentNode, int prettyFlags)
{
	if (!node)
		return false;

	switch (nodeTag(node))
	{
		case T_Var:
		case T_Const:
		case T_Param:
		case T_CoerceToDomainValue:
		case T_SetToDefault:
		case T_CurrentOfExpr:
			/* single words: always simple */
			return true;

		case T_ArrayRef:
		case T_ArrayExpr:
		case T_RowExpr:
		case T_CoalesceExpr:
		case T_MinMaxExpr:
		case T_XmlExpr:
		case T_NullIfExpr:
		case T_Aggref:
		case T_WindowFunc:
		case T_FuncExpr:
			/* function-like: name(..) or name[..] */
			return true;

			/* CASE keywords act as parentheses */
		case T_CaseExpr:
			return true;

		case T_FieldSelect:

			/*
			 * appears simple since . has top precedence, unless parent is
			 * T_FieldSelect itself!
			 */
			return (IsA(parentNode, FieldSelect) ? false : true);

		case T_FieldStore:

			/*
			 * treat like FieldSelect (probably doesn't matter)
			 */
			return (IsA(parentNode, FieldStore) ? false : true);

		case T_CoerceToDomain:
			/* maybe simple, check args */
			return isSimpleNode((Node *) ((CoerceToDomain *) node)->arg,
								node, prettyFlags);
		case T_RelabelType:
			return isSimpleNode((Node *) ((RelabelType *) node)->arg,
								node, prettyFlags);
		case T_CoerceViaIO:
			return isSimpleNode((Node *) ((CoerceViaIO *) node)->arg,
								node, prettyFlags);
		case T_ArrayCoerceExpr:
			return isSimpleNode((Node *) ((ArrayCoerceExpr *) node)->arg,
								node, prettyFlags);
		case T_ConvertRowtypeExpr:
			return isSimpleNode((Node *) ((ConvertRowtypeExpr *) node)->arg,
								node, prettyFlags);

		case T_OpExpr:
			{
				/* depends on parent node type; needs further checking */
				if (prettyFlags & PRETTYFLAG_PAREN && IsA(parentNode, OpExpr))
				{
					const char *op;
					const char *parentOp;
					bool		is_lopriop;
					bool		is_hipriop;
					bool		is_lopriparent;
					bool		is_hipriparent;

					op = get_simple_binary_op_name((OpExpr *) node);
					if (!op)
						return false;

					/* We know only the basic operators + - and * / % */
					is_lopriop = (strchr("+-", *op) != NULL);
					is_hipriop = (strchr("*/%", *op) != NULL);
					if (!(is_lopriop || is_hipriop))
						return false;

					parentOp = get_simple_binary_op_name((OpExpr *) parentNode);
					if (!parentOp)
						return false;

					is_lopriparent = (strchr("+-", *parentOp) != NULL);
					is_hipriparent = (strchr("*/%", *parentOp) != NULL);
					if (!(is_lopriparent || is_hipriparent))
						return false;

					if (is_hipriop && is_lopriparent)
						return true;	/* op binds tighter than parent */

					if (is_lopriop && is_hipriparent)
						return false;

					/*
					 * Operators are same priority --- can skip parens only if
					 * we have (a - b) - c, not a - (b - c).
					 */
					if (node == (Node *) linitial(((OpExpr *) parentNode)->args))
						return true;

					return false;
				}
				/* else do the same stuff as for T_SubLink et al. */
				/* FALL THROUGH */
			}

		case T_SubLink:
		case T_NullTest:
		case T_BooleanTest:
		case T_DistinctExpr:
			switch (nodeTag(parentNode))
			{
				case T_FuncExpr:
					{
						/* special handling for casts */
						CoercionForm type = ((FuncExpr *) parentNode)->funcformat;

						if (type == COERCE_EXPLICIT_CAST ||
							type == COERCE_IMPLICIT_CAST)
							return false;
						return true;	/* own parentheses */
					}
				case T_BoolExpr:		/* lower precedence */
				case T_ArrayRef:		/* other separators */
				case T_ArrayExpr:		/* other separators */
				case T_RowExpr:	/* other separators */
				case T_CoalesceExpr:	/* own parentheses */
				case T_MinMaxExpr:		/* own parentheses */
				case T_XmlExpr:	/* own parentheses */
				case T_NullIfExpr:		/* other separators */
				case T_Aggref:	/* own parentheses */
				case T_WindowFunc:		/* own parentheses */
				case T_CaseExpr:		/* other separators */
					return true;
				default:
					return false;
			}

		case T_BoolExpr:
			switch (nodeTag(parentNode))
			{
				case T_BoolExpr:
					if (prettyFlags & PRETTYFLAG_PAREN)
					{
						BoolExprType type;
						BoolExprType parentType;

						type = ((BoolExpr *) node)->boolop;
						parentType = ((BoolExpr *) parentNode)->boolop;
						switch (type)
						{
							case NOT_EXPR:
							case AND_EXPR:
								if (parentType == AND_EXPR || parentType == OR_EXPR)
									return true;
								break;
							case OR_EXPR:
								if (parentType == OR_EXPR)
									return true;
								break;
						}
					}
					return false;
				case T_FuncExpr:
					{
						/* special handling for casts */
						CoercionForm type = ((FuncExpr *) parentNode)->funcformat;

						if (type == COERCE_EXPLICIT_CAST ||
							type == COERCE_IMPLICIT_CAST)
							return false;
						return true;	/* own parentheses */
					}
				case T_ArrayRef:		/* other separators */
				case T_ArrayExpr:		/* other separators */
				case T_RowExpr:	/* other separators */
				case T_CoalesceExpr:	/* own parentheses */
				case T_MinMaxExpr:		/* own parentheses */
				case T_XmlExpr:	/* own parentheses */
				case T_NullIfExpr:		/* other separators */
				case T_Aggref:	/* own parentheses */
				case T_WindowFunc:		/* own parentheses */
				case T_CaseExpr:		/* other separators */
					return true;
				default:
					return false;
			}

		default:
			break;
	}
	/* those we don't know: in dubio complexo */
	return false;
}


/*
 * appendContextKeyword - append a keyword to buffer
 *
 * If prettyPrint is enabled, perform a line break, and adjust indentation.
 * Otherwise, just append the keyword.
 */
static void
appendContextKeyword(deparse_context *context, const char *str,
					 int indentBefore, int indentAfter, int indentPlus)
{
	if (PRETTY_INDENT(context))
	{
		context->indentLevel += indentBefore;

		appendStringInfoChar(context->buf, '\n');
		appendStringInfoSpaces(context->buf,
							   Max(context->indentLevel, 0) + indentPlus);
		appendStringInfoString(context->buf, str);

		context->indentLevel += indentAfter;
		if (context->indentLevel < 0)
			context->indentLevel = 0;
	}
	else
		appendStringInfoString(context->buf, str);
}

/*
 * get_rule_expr_paren	- deparse expr using get_rule_expr,
 * embracing the string with parentheses if necessary for prettyPrint.
 *
 * Never embrace if prettyFlags=0, because it's done in the calling node.
 *
 * Any node that does *not* embrace its argument node by sql syntax (with
 * parentheses, non-operator keywords like CASE/WHEN/ON, or comma etc) should
 * use get_rule_expr_paren instead of get_rule_expr so parentheses can be
 * added.
 */
static void
get_rule_expr_paren(Node *node, deparse_context *context,
					bool showimplicit, Node *parentNode)
{
	bool		need_paren;

	need_paren = PRETTY_PAREN(context) &&
		!isSimpleNode(node, parentNode, context->prettyFlags);

	if (need_paren)
		appendStringInfoChar(context->buf, '(');

	get_rule_expr(node, context, showimplicit);

	if (need_paren)
		appendStringInfoChar(context->buf, ')');
}


/* ----------
 * get_rule_expr			- Parse back an expression
 *
 * Note: showimplicit determines whether we display any implicit cast that
 * is present at the top of the expression tree.  It is a passed argument,
 * not a field of the context struct, because we change the value as we
 * recurse down into the expression.  In general we suppress implicit casts
 * when the result type is known with certainty (eg, the arguments of an
 * OR must be boolean).  We display implicit casts for arguments of functions
 * and operators, since this is needed to be certain that the same function
 * or operator will be chosen when the expression is re-parsed.
 * ----------
 */
static void
get_rule_expr(Node *node, deparse_context *context,
			  bool showimplicit)
{
	StringInfo	buf = context->buf;

	if (node == NULL)
		return;

	/*
	 * Each level of get_rule_expr must emit an indivisible term
	 * (parenthesized if necessary) to ensure result is reparsed into the same
	 * expression tree.  The only exception is that when the input is a List,
	 * we emit the component items comma-separated with no surrounding
	 * decoration; this is convenient for most callers.
	 */
	switch (nodeTag(node))
	{
		case T_Var:
			(void) get_variable((Var *) node, 0, false, context);
			break;

		case T_Const:
			get_const_expr((Const *) node, context, 0);
			break;

		case T_Param:
			get_parameter((Param *) node, context);
			break;

		case T_Aggref:
			get_agg_expr((Aggref *) node, context);
			break;

		case T_WindowFunc:
			get_windowfunc_expr((WindowFunc *) node, context);
			break;

		case T_ArrayRef:
			{
				ArrayRef   *aref = (ArrayRef *) node;
				bool		need_parens;

				/*
				 * If the argument is a CaseTestExpr, we must be inside a
				 * FieldStore, ie, we are assigning to an element of an array
				 * within a composite column.  Since we already punted on
				 * displaying the FieldStore's target information, just punt
				 * here too, and display only the assignment source
				 * expression.
				 */
				if (IsA(aref->refexpr, CaseTestExpr))
				{
					Assert(aref->refassgnexpr);
					get_rule_expr((Node *) aref->refassgnexpr,
								  context, showimplicit);
					break;
				}

				/*
				 * Parenthesize the argument unless it's a simple Var or a
				 * FieldSelect.  (In particular, if it's another ArrayRef, we
				 * *must* parenthesize to avoid confusion.)
				 */
				need_parens = !IsA(aref->refexpr, Var) &&
					!IsA(aref->refexpr, FieldSelect);
				if (need_parens)
					appendStringInfoChar(buf, '(');
				get_rule_expr((Node *) aref->refexpr, context, showimplicit);
				if (need_parens)
					appendStringInfoChar(buf, ')');

				/*
				 * If there's a refassgnexpr, we want to print the node in the
				 * format "array[subscripts] := refassgnexpr".	This is not
				 * legal SQL, so decompilation of INSERT or UPDATE statements
				 * should always use processIndirection as part of the
				 * statement-level syntax.	We should only see this when
				 * EXPLAIN tries to print the targetlist of a plan resulting
				 * from such a statement.
				 */
				if (aref->refassgnexpr)
				{
					Node	   *refassgnexpr;

					/*
					 * Use processIndirection to print this node's subscripts
					 * as well as any additional field selections or
					 * subscripting in immediate descendants.  It returns the
					 * RHS expr that is actually being "assigned".
					 */
					refassgnexpr = processIndirection(node, context, true);
					appendStringInfoString(buf, " := ");
					get_rule_expr(refassgnexpr, context, showimplicit);
				}
				else
				{
					/* Just an ordinary array fetch, so print subscripts */
					printSubscripts(aref, context);
				}
			}
			break;

		case T_FuncExpr:
			get_func_expr((FuncExpr *) node, context, showimplicit);
			break;

		case T_NamedArgExpr:
			{
				NamedArgExpr *na = (NamedArgExpr *) node;

				appendStringInfo(buf, "%s := ", quote_identifier(na->name));
				get_rule_expr((Node *) na->arg, context, showimplicit);
			}
			break;

		case T_OpExpr:
			get_oper_expr((OpExpr *) node, context);
			break;

		case T_DistinctExpr:
			{
				DistinctExpr *expr = (DistinctExpr *) node;
				List	   *args = expr->args;
				Node	   *arg1 = (Node *) linitial(args);
				Node	   *arg2 = (Node *) lsecond(args);

				if (!PRETTY_PAREN(context))
					appendStringInfoChar(buf, '(');
				get_rule_expr_paren(arg1, context, true, node);
				appendStringInfo(buf, " IS DISTINCT FROM ");
				get_rule_expr_paren(arg2, context, true, node);
				if (!PRETTY_PAREN(context))
					appendStringInfoChar(buf, ')');
			}
			break;

		case T_NullIfExpr:
			{
				NullIfExpr *nullifexpr = (NullIfExpr *) node;

				appendStringInfo(buf, "NULLIF(");
				get_rule_expr((Node *) nullifexpr->args, context, true);
				appendStringInfoChar(buf, ')');
			}
			break;

		case T_ScalarArrayOpExpr:
			{
				ScalarArrayOpExpr *expr = (ScalarArrayOpExpr *) node;
				List	   *args = expr->args;
				Node	   *arg1 = (Node *) linitial(args);
				Node	   *arg2 = (Node *) lsecond(args);

				if (!PRETTY_PAREN(context))
					appendStringInfoChar(buf, '(');
				get_rule_expr_paren(arg1, context, true, node);
				appendStringInfo(buf, " %s %s (",
								 generate_operator_name(expr->opno,
														exprType(arg1),
									  get_base_element_type(exprType(arg2))),
								 expr->useOr ? "ANY" : "ALL");
				get_rule_expr_paren(arg2, context, true, node);
				appendStringInfoChar(buf, ')');
				if (!PRETTY_PAREN(context))
					appendStringInfoChar(buf, ')');
			}
			break;

		case T_BoolExpr:
			{
				BoolExpr   *expr = (BoolExpr *) node;
				Node	   *first_arg = linitial(expr->args);
				ListCell   *arg = lnext(list_head(expr->args));

				switch (expr->boolop)
				{
					case AND_EXPR:
						if (!PRETTY_PAREN(context))
							appendStringInfoChar(buf, '(');
						get_rule_expr_paren(first_arg, context,
											false, node);
						while (arg)
						{
							appendStringInfo(buf, " AND ");
							get_rule_expr_paren((Node *) lfirst(arg), context,
												false, node);
							arg = lnext(arg);
						}
						if (!PRETTY_PAREN(context))
							appendStringInfoChar(buf, ')');
						break;

					case OR_EXPR:
						if (!PRETTY_PAREN(context))
							appendStringInfoChar(buf, '(');
						get_rule_expr_paren(first_arg, context,
											false, node);
						while (arg)
						{
							appendStringInfo(buf, " OR ");
							get_rule_expr_paren((Node *) lfirst(arg), context,
												false, node);
							arg = lnext(arg);
						}
						if (!PRETTY_PAREN(context))
							appendStringInfoChar(buf, ')');
						break;

					case NOT_EXPR:
						if (!PRETTY_PAREN(context))
							appendStringInfoChar(buf, '(');
						appendStringInfo(buf, "NOT ");
						get_rule_expr_paren(first_arg, context,
											false, node);
						if (!PRETTY_PAREN(context))
							appendStringInfoChar(buf, ')');
						break;

					default:
						elog(ERROR, "unrecognized boolop: %d",
							 (int) expr->boolop);
				}
			}
			break;

		case T_SubLink:
			get_sublink_expr((SubLink *) node, context);
			break;

		case T_SubPlan:
			{
				SubPlan    *subplan = (SubPlan *) node;

				/*
				 * We cannot see an already-planned subplan in rule deparsing,
				 * only while EXPLAINing a query plan.	We don't try to
				 * reconstruct the original SQL, just reference the subplan
				 * that appears elsewhere in EXPLAIN's result.
				 */
				if (subplan->useHashTable)
					appendStringInfo(buf, "(hashed %s)", subplan->plan_name);
				else
					appendStringInfo(buf, "(%s)", subplan->plan_name);
			}
			break;

		case T_AlternativeSubPlan:
			{
				AlternativeSubPlan *asplan = (AlternativeSubPlan *) node;
				ListCell   *lc;

				/* As above, this can only happen during EXPLAIN */
				appendStringInfo(buf, "(alternatives: ");
				foreach(lc, asplan->subplans)
				{
					SubPlan    *splan = (SubPlan *) lfirst(lc);

					Assert(IsA(splan, SubPlan));
					if (splan->useHashTable)
						appendStringInfo(buf, "hashed %s", splan->plan_name);
					else
						appendStringInfo(buf, "%s", splan->plan_name);
					if (lnext(lc))
						appendStringInfo(buf, " or ");
				}
				appendStringInfo(buf, ")");
			}
			break;

		case T_FieldSelect:
			{
				FieldSelect *fselect = (FieldSelect *) node;
				Node	   *arg = (Node *) fselect->arg;
				int			fno = fselect->fieldnum;
				const char *fieldname;
				bool		need_parens;

				/*
				 * Parenthesize the argument unless it's an ArrayRef or
				 * another FieldSelect.  Note in particular that it would be
				 * WRONG to not parenthesize a Var argument; simplicity is not
				 * the issue here, having the right number of names is.
				 */
				need_parens = !IsA(arg, ArrayRef) &&!IsA(arg, FieldSelect);
				if (need_parens)
					appendStringInfoChar(buf, '(');
				get_rule_expr(arg, context, true);
				if (need_parens)
					appendStringInfoChar(buf, ')');

				/*
				 * Get and print the field name.
				 */
				fieldname = get_name_for_var_field((Var *) arg, fno,
												   0, context);
				appendStringInfo(buf, ".%s", quote_identifier(fieldname));
			}
			break;

		case T_FieldStore:
			{
				FieldStore *fstore = (FieldStore *) node;
				bool		need_parens;

				/*
				 * There is no good way to represent a FieldStore as real SQL,
				 * so decompilation of INSERT or UPDATE statements should
				 * always use processIndirection as part of the
				 * statement-level syntax.	We should only get here when
				 * EXPLAIN tries to print the targetlist of a plan resulting
				 * from such a statement.  The plan case is even harder than
				 * ordinary rules would be, because the planner tries to
				 * collapse multiple assignments to the same field or subfield
				 * into one FieldStore; so we can see a list of target fields
				 * not just one, and the arguments could be FieldStores
				 * themselves.	We don't bother to try to print the target
				 * field names; we just print the source arguments, with a
				 * ROW() around them if there's more than one.  This isn't
				 * terribly complete, but it's probably good enough for
				 * EXPLAIN's purposes; especially since anything more would be
				 * either hopelessly confusing or an even poorer
				 * representation of what the plan is actually doing.
				 */
				need_parens = (list_length(fstore->newvals) != 1);
				if (need_parens)
					appendStringInfoString(buf, "ROW(");
				get_rule_expr((Node *) fstore->newvals, context, showimplicit);
				if (need_parens)
					appendStringInfoChar(buf, ')');
			}
			break;

		case T_RelabelType:
			{
				RelabelType *relabel = (RelabelType *) node;
				Node	   *arg = (Node *) relabel->arg;

				if (relabel->relabelformat == COERCE_IMPLICIT_CAST &&
					!showimplicit)
				{
					/* don't show the implicit cast */
					get_rule_expr_paren(arg, context, false, node);
				}
				else
				{
					get_coercion_expr(arg, context,
									  relabel->resulttype,
									  relabel->resulttypmod,
									  node);
				}
			}
			break;

		case T_CoerceViaIO:
			{
				CoerceViaIO *iocoerce = (CoerceViaIO *) node;
				Node	   *arg = (Node *) iocoerce->arg;

				if (iocoerce->coerceformat == COERCE_IMPLICIT_CAST &&
					!showimplicit)
				{
					/* don't show the implicit cast */
					get_rule_expr_paren(arg, context, false, node);
				}
				else
				{
					get_coercion_expr(arg, context,
									  iocoerce->resulttype,
									  -1,
									  node);
				}
			}
			break;

		case T_ArrayCoerceExpr:
			{
				ArrayCoerceExpr *acoerce = (ArrayCoerceExpr *) node;
				Node	   *arg = (Node *) acoerce->arg;

				if (acoerce->coerceformat == COERCE_IMPLICIT_CAST &&
					!showimplicit)
				{
					/* don't show the implicit cast */
					get_rule_expr_paren(arg, context, false, node);
				}
				else
				{
					get_coercion_expr(arg, context,
									  acoerce->resulttype,
									  acoerce->resulttypmod,
									  node);
				}
			}
			break;

		case T_ConvertRowtypeExpr:
			{
				ConvertRowtypeExpr *convert = (ConvertRowtypeExpr *) node;
				Node	   *arg = (Node *) convert->arg;

				if (convert->convertformat == COERCE_IMPLICIT_CAST &&
					!showimplicit)
				{
					/* don't show the implicit cast */
					get_rule_expr_paren(arg, context, false, node);
				}
				else
				{
					get_coercion_expr(arg, context,
									  convert->resulttype, -1,
									  node);
				}
			}
			break;

		case T_CollateExpr:
			{
				CollateExpr *collate = (CollateExpr *) node;
				Node	   *arg = (Node *) collate->arg;

				if (!PRETTY_PAREN(context))
					appendStringInfoChar(buf, '(');
				get_rule_expr_paren(arg, context, showimplicit, node);
				appendStringInfo(buf, " COLLATE %s",
								 generate_collation_name(collate->collOid));
				if (!PRETTY_PAREN(context))
					appendStringInfoChar(buf, ')');
			}
			break;

		case T_CaseExpr:
			{
				CaseExpr   *caseexpr = (CaseExpr *) node;
				ListCell   *temp;

				appendContextKeyword(context, "CASE",
									 0, PRETTYINDENT_VAR, 0);
				if (caseexpr->arg)
				{
					appendStringInfoChar(buf, ' ');
					get_rule_expr((Node *) caseexpr->arg, context, true);
				}
				foreach(temp, caseexpr->args)
				{
					CaseWhen   *when = (CaseWhen *) lfirst(temp);
					Node	   *w = (Node *) when->expr;

					if (caseexpr->arg)
					{
						/*
						 * The parser should have produced WHEN clauses of the
						 * form "CaseTestExpr = RHS", possibly with an
						 * implicit coercion inserted above the CaseTestExpr.
						 * For accurate decompilation of rules it's essential
						 * that we show just the RHS.  However in an
						 * expression that's been through the optimizer, the
						 * WHEN clause could be almost anything (since the
						 * equality operator could have been expanded into an
						 * inline function).  If we don't recognize the form
						 * of the WHEN clause, just punt and display it as-is.
						 */
						if (IsA(w, OpExpr))
						{
							List	   *args = ((OpExpr *) w)->args;

							if (list_length(args) == 2 &&
								IsA(strip_implicit_coercions(linitial(args)),
									CaseTestExpr))
								w = (Node *) lsecond(args);
						}
					}

					if (!PRETTY_INDENT(context))
						appendStringInfoChar(buf, ' ');
					appendContextKeyword(context, "WHEN ",
										 0, 0, 0);
					get_rule_expr(w, context, false);
					appendStringInfo(buf, " THEN ");
					get_rule_expr((Node *) when->result, context, true);
				}
				if (!PRETTY_INDENT(context))
					appendStringInfoChar(buf, ' ');
				appendContextKeyword(context, "ELSE ",
									 0, 0, 0);
				get_rule_expr((Node *) caseexpr->defresult, context, true);
				if (!PRETTY_INDENT(context))
					appendStringInfoChar(buf, ' ');
				appendContextKeyword(context, "END",
									 -PRETTYINDENT_VAR, 0, 0);
			}
			break;

		case T_CaseTestExpr:
			{
				/*
				 * Normally we should never get here, since for expressions
				 * that can contain this node type we attempt to avoid
				 * recursing to it.  But in an optimized expression we might
				 * be unable to avoid that (see comments for CaseExpr).  If we
				 * do see one, print it as CASE_TEST_EXPR.
				 */
				appendStringInfo(buf, "CASE_TEST_EXPR");
			}
			break;

		case T_ArrayExpr:
			{
				ArrayExpr  *arrayexpr = (ArrayExpr *) node;

				appendStringInfo(buf, "ARRAY[");
				get_rule_expr((Node *) arrayexpr->elements, context, true);
				appendStringInfoChar(buf, ']');

				/*
				 * If the array isn't empty, we assume its elements are
				 * coerced to the desired type.  If it's empty, though, we
				 * need an explicit coercion to the array type.
				 */
				if (arrayexpr->elements == NIL)
					appendStringInfo(buf, "::%s",
					  format_type_with_typemod(arrayexpr->array_typeid, -1));
			}
			break;

		case T_RowExpr:
			{
				RowExpr    *rowexpr = (RowExpr *) node;
				TupleDesc	tupdesc = NULL;
				ListCell   *arg;
				int			i;
				char	   *sep;

				/*
				 * If it's a named type and not RECORD, we may have to skip
				 * dropped columns and/or claim there are NULLs for added
				 * columns.
				 */
				if (rowexpr->row_typeid != RECORDOID)
				{
					tupdesc = lookup_rowtype_tupdesc(rowexpr->row_typeid, -1);
					Assert(list_length(rowexpr->args) <= tupdesc->natts);
				}

				/*
				 * SQL99 allows "ROW" to be omitted when there is more than
				 * one column, but for simplicity we always print it.
				 */
				appendStringInfo(buf, "ROW(");
				sep = "";
				i = 0;
				foreach(arg, rowexpr->args)
				{
					Node	   *e = (Node *) lfirst(arg);

					if (tupdesc == NULL ||
						!tupdesc->attrs[i]->attisdropped)
					{
						appendStringInfoString(buf, sep);
						get_rule_expr(e, context, true);
						sep = ", ";
					}
					i++;
				}
				if (tupdesc != NULL)
				{
					while (i < tupdesc->natts)
					{
						if (!tupdesc->attrs[i]->attisdropped)
						{
							appendStringInfoString(buf, sep);
							appendStringInfo(buf, "NULL");
							sep = ", ";
						}
						i++;
					}

					ReleaseTupleDesc(tupdesc);
				}
				appendStringInfo(buf, ")");
				if (rowexpr->row_format == COERCE_EXPLICIT_CAST)
					appendStringInfo(buf, "::%s",
						  format_type_with_typemod(rowexpr->row_typeid, -1));
			}
			break;

		case T_RowCompareExpr:
			{
				RowCompareExpr *rcexpr = (RowCompareExpr *) node;
				ListCell   *arg;
				char	   *sep;

				/*
				 * SQL99 allows "ROW" to be omitted when there is more than
				 * one column, but for simplicity we always print it.
				 */
				appendStringInfo(buf, "(ROW(");
				sep = "";
				foreach(arg, rcexpr->largs)
				{
					Node	   *e = (Node *) lfirst(arg);

					appendStringInfoString(buf, sep);
					get_rule_expr(e, context, true);
					sep = ", ";
				}

				/*
				 * We assume that the name of the first-column operator will
				 * do for all the rest too.  This is definitely open to
				 * failure, eg if some but not all operators were renamed
				 * since the construct was parsed, but there seems no way to
				 * be perfect.
				 */
				appendStringInfo(buf, ") %s ROW(",
						  generate_operator_name(linitial_oid(rcexpr->opnos),
										   exprType(linitial(rcexpr->largs)),
										 exprType(linitial(rcexpr->rargs))));
				sep = "";
				foreach(arg, rcexpr->rargs)
				{
					Node	   *e = (Node *) lfirst(arg);

					appendStringInfoString(buf, sep);
					get_rule_expr(e, context, true);
					sep = ", ";
				}
				appendStringInfo(buf, "))");
			}
			break;

		case T_CoalesceExpr:
			{
				CoalesceExpr *coalesceexpr = (CoalesceExpr *) node;

				appendStringInfo(buf, "COALESCE(");
				get_rule_expr((Node *) coalesceexpr->args, context, true);
				appendStringInfoChar(buf, ')');
			}
			break;

		case T_MinMaxExpr:
			{
				MinMaxExpr *minmaxexpr = (MinMaxExpr *) node;

				switch (minmaxexpr->op)
				{
					case IS_GREATEST:
						appendStringInfo(buf, "GREATEST(");
						break;
					case IS_LEAST:
						appendStringInfo(buf, "LEAST(");
						break;
				}
				get_rule_expr((Node *) minmaxexpr->args, context, true);
				appendStringInfoChar(buf, ')');
			}
			break;

		case T_XmlExpr:
			{
				XmlExpr    *xexpr = (XmlExpr *) node;
				bool		needcomma = false;
				ListCell   *arg;
				ListCell   *narg;
				Const	   *con;

				switch (xexpr->op)
				{
					case IS_XMLCONCAT:
						appendStringInfoString(buf, "XMLCONCAT(");
						break;
					case IS_XMLELEMENT:
						appendStringInfoString(buf, "XMLELEMENT(");
						break;
					case IS_XMLFOREST:
						appendStringInfoString(buf, "XMLFOREST(");
						break;
					case IS_XMLPARSE:
						appendStringInfoString(buf, "XMLPARSE(");
						break;
					case IS_XMLPI:
						appendStringInfoString(buf, "XMLPI(");
						break;
					case IS_XMLROOT:
						appendStringInfoString(buf, "XMLROOT(");
						break;
					case IS_XMLSERIALIZE:
						appendStringInfoString(buf, "XMLSERIALIZE(");
						break;
					case IS_DOCUMENT:
						break;
				}
				if (xexpr->op == IS_XMLPARSE || xexpr->op == IS_XMLSERIALIZE)
				{
					if (xexpr->xmloption == XMLOPTION_DOCUMENT)
						appendStringInfoString(buf, "DOCUMENT ");
					else
						appendStringInfoString(buf, "CONTENT ");
				}
				if (xexpr->name)
				{
					appendStringInfo(buf, "NAME %s",
									 quote_identifier(map_xml_name_to_sql_identifier(xexpr->name)));
					needcomma = true;
				}
				if (xexpr->named_args)
				{
					if (xexpr->op != IS_XMLFOREST)
					{
						if (needcomma)
							appendStringInfoString(buf, ", ");
						appendStringInfoString(buf, "XMLATTRIBUTES(");
						needcomma = false;
					}
					forboth(arg, xexpr->named_args, narg, xexpr->arg_names)
					{
						Node	   *e = (Node *) lfirst(arg);
						char	   *argname = strVal(lfirst(narg));

						if (needcomma)
							appendStringInfoString(buf, ", ");
						get_rule_expr((Node *) e, context, true);
						appendStringInfo(buf, " AS %s",
										 quote_identifier(map_xml_name_to_sql_identifier(argname)));
						needcomma = true;
					}
					if (xexpr->op != IS_XMLFOREST)
						appendStringInfoChar(buf, ')');
				}
				if (xexpr->args)
				{
					if (needcomma)
						appendStringInfoString(buf, ", ");
					switch (xexpr->op)
					{
						case IS_XMLCONCAT:
						case IS_XMLELEMENT:
						case IS_XMLFOREST:
						case IS_XMLPI:
						case IS_XMLSERIALIZE:
							/* no extra decoration needed */
							get_rule_expr((Node *) xexpr->args, context, true);
							break;
						case IS_XMLPARSE:
							Assert(list_length(xexpr->args) == 2);

							get_rule_expr((Node *) linitial(xexpr->args),
										  context, true);

							con = (Const *) lsecond(xexpr->args);
							Assert(IsA(con, Const));
							Assert(!con->constisnull);
							if (DatumGetBool(con->constvalue))
								appendStringInfoString(buf,
													 " PRESERVE WHITESPACE");
							else
								appendStringInfoString(buf,
													   " STRIP WHITESPACE");
							break;
						case IS_XMLROOT:
							Assert(list_length(xexpr->args) == 3);

							get_rule_expr((Node *) linitial(xexpr->args),
										  context, true);

							appendStringInfoString(buf, ", VERSION ");
							con = (Const *) lsecond(xexpr->args);
							if (IsA(con, Const) &&
								con->constisnull)
								appendStringInfoString(buf, "NO VALUE");
							else
								get_rule_expr((Node *) con, context, false);

							con = (Const *) lthird(xexpr->args);
							Assert(IsA(con, Const));
							if (con->constisnull)
								 /* suppress STANDALONE NO VALUE */ ;
							else
							{
								switch (DatumGetInt32(con->constvalue))
								{
									case XML_STANDALONE_YES:
										appendStringInfoString(buf,
														 ", STANDALONE YES");
										break;
									case XML_STANDALONE_NO:
										appendStringInfoString(buf,
														  ", STANDALONE NO");
										break;
									case XML_STANDALONE_NO_VALUE:
										appendStringInfoString(buf,
													", STANDALONE NO VALUE");
										break;
									default:
										break;
								}
							}
							break;
						case IS_DOCUMENT:
							get_rule_expr_paren((Node *) xexpr->args, context, false, node);
							break;
					}

				}
				if (xexpr->op == IS_XMLSERIALIZE)
					appendStringInfo(buf, " AS %s",
									 format_type_with_typemod(xexpr->type,
															  xexpr->typmod));
				if (xexpr->op == IS_DOCUMENT)
					appendStringInfoString(buf, " IS DOCUMENT");
				else
					appendStringInfoChar(buf, ')');
			}
			break;

		case T_NullTest:
			{
				NullTest   *ntest = (NullTest *) node;

				if (!PRETTY_PAREN(context))
					appendStringInfoChar(buf, '(');
				get_rule_expr_paren((Node *) ntest->arg, context, true, node);
				switch (ntest->nulltesttype)
				{
					case IS_NULL:
						appendStringInfo(buf, " IS NULL");
						break;
					case IS_NOT_NULL:
						appendStringInfo(buf, " IS NOT NULL");
						break;
					default:
						elog(ERROR, "unrecognized nulltesttype: %d",
							 (int) ntest->nulltesttype);
				}
				if (!PRETTY_PAREN(context))
					appendStringInfoChar(buf, ')');
			}
			break;

		case T_BooleanTest:
			{
				BooleanTest *btest = (BooleanTest *) node;

				if (!PRETTY_PAREN(context))
					appendStringInfoChar(buf, '(');
				get_rule_expr_paren((Node *) btest->arg, context, false, node);
				switch (btest->booltesttype)
				{
					case IS_TRUE:
						appendStringInfo(buf, " IS TRUE");
						break;
					case IS_NOT_TRUE:
						appendStringInfo(buf, " IS NOT TRUE");
						break;
					case IS_FALSE:
						appendStringInfo(buf, " IS FALSE");
						break;
					case IS_NOT_FALSE:
						appendStringInfo(buf, " IS NOT FALSE");
						break;
					case IS_UNKNOWN:
						appendStringInfo(buf, " IS UNKNOWN");
						break;
					case IS_NOT_UNKNOWN:
						appendStringInfo(buf, " IS NOT UNKNOWN");
						break;
					default:
						elog(ERROR, "unrecognized booltesttype: %d",
							 (int) btest->booltesttype);
				}
				if (!PRETTY_PAREN(context))
					appendStringInfoChar(buf, ')');
			}
			break;

		case T_CoerceToDomain:
			{
				CoerceToDomain *ctest = (CoerceToDomain *) node;
				Node	   *arg = (Node *) ctest->arg;

				if (ctest->coercionformat == COERCE_IMPLICIT_CAST &&
					!showimplicit)
				{
					/* don't show the implicit cast */
					get_rule_expr(arg, context, false);
				}
				else
				{
					get_coercion_expr(arg, context,
									  ctest->resulttype,
									  ctest->resulttypmod,
									  node);
				}
			}
			break;

		case T_CoerceToDomainValue:
			appendStringInfo(buf, "VALUE");
			break;

		case T_SetToDefault:
			appendStringInfo(buf, "DEFAULT");
			break;

		case T_CurrentOfExpr:
			{
				CurrentOfExpr *cexpr = (CurrentOfExpr *) node;

				if (cexpr->cursor_name)
					appendStringInfo(buf, "CURRENT OF %s",
									 quote_identifier(cexpr->cursor_name));
				else
					appendStringInfo(buf, "CURRENT OF $%d",
									 cexpr->cursor_param);
			}
			break;

		case T_List:
			{
				char	   *sep;
				ListCell   *l;

				sep = "";
				foreach(l, (List *) node)
				{
					appendStringInfoString(buf, sep);
					get_rule_expr((Node *) lfirst(l), context, showimplicit);
					sep = ", ";
				}
			}
			break;

		default:
			elog(ERROR, "unrecognized node type: %d", (int) nodeTag(node));
			break;
	}
}


/*
 * get_oper_expr			- Parse back an OpExpr node
 */
static void
get_oper_expr(OpExpr *expr, deparse_context *context)
{
	StringInfo	buf = context->buf;
	Oid			opno = expr->opno;
	List	   *args = expr->args;

	if (!PRETTY_PAREN(context))
		appendStringInfoChar(buf, '(');
	if (list_length(args) == 2)
	{
		/* binary operator */
		Node	   *arg1 = (Node *) linitial(args);
		Node	   *arg2 = (Node *) lsecond(args);

		get_rule_expr_paren(arg1, context, true, (Node *) expr);
		appendStringInfo(buf, " %s ",
						 generate_operator_name(opno,
												exprType(arg1),
												exprType(arg2)));
		get_rule_expr_paren(arg2, context, true, (Node *) expr);
	}
	else
	{
		/* unary operator --- but which side? */
		Node	   *arg = (Node *) linitial(args);
		HeapTuple	tp;
		Form_pg_operator optup;

		tp = SearchSysCache1(OPEROID, ObjectIdGetDatum(opno));
		if (!HeapTupleIsValid(tp))
			elog(ERROR, "cache lookup failed for operator %u", opno);
		optup = (Form_pg_operator) GETSTRUCT(tp);
		switch (optup->oprkind)
		{
			case 'l':
				appendStringInfo(buf, "%s ",
								 generate_operator_name(opno,
														InvalidOid,
														exprType(arg)));
				get_rule_expr_paren(arg, context, true, (Node *) expr);
				break;
			case 'r':
				get_rule_expr_paren(arg, context, true, (Node *) expr);
				appendStringInfo(buf, " %s",
								 generate_operator_name(opno,
														exprType(arg),
														InvalidOid));
				break;
			default:
				elog(ERROR, "bogus oprkind: %d", optup->oprkind);
		}
		ReleaseSysCache(tp);
	}
	if (!PRETTY_PAREN(context))
		appendStringInfoChar(buf, ')');
}

/*
 * get_func_expr			- Parse back a FuncExpr node
 */
static void
get_func_expr(FuncExpr *expr, deparse_context *context,
			  bool showimplicit)
{
	StringInfo	buf = context->buf;
	Oid			funcoid = expr->funcid;
	Oid			argtypes[FUNC_MAX_ARGS];
	int			nargs;
	List	   *argnames;
	bool		is_variadic;
	ListCell   *l;

	/*
	 * If the function call came from an implicit coercion, then just show the
	 * first argument --- unless caller wants to see implicit coercions.
	 */
	if (expr->funcformat == COERCE_IMPLICIT_CAST && !showimplicit)
	{
		get_rule_expr_paren((Node *) linitial(expr->args), context,
							false, (Node *) expr);
		return;
	}

	/*
	 * If the function call came from a cast, then show the first argument
	 * plus an explicit cast operation.
	 */
	if (expr->funcformat == COERCE_EXPLICIT_CAST ||
		expr->funcformat == COERCE_IMPLICIT_CAST)
	{
		Node	   *arg = linitial(expr->args);
		Oid			rettype = expr->funcresulttype;
		int32		coercedTypmod;

		/* Get the typmod if this is a length-coercion function */
		(void) exprIsLengthCoercion((Node *) expr, &coercedTypmod);

		get_coercion_expr(arg, context,
						  rettype, coercedTypmod,
						  (Node *) expr);

		return;
	}

	/*
	 * Normal function: display as proname(args).  First we need to extract
	 * the argument datatypes.
	 */
	if (list_length(expr->args) > FUNC_MAX_ARGS)
		ereport(ERROR,
				(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
				 errmsg("too many arguments")));
	nargs = 0;
	argnames = NIL;
	foreach(l, expr->args)
	{
		Node	   *arg = (Node *) lfirst(l);

		if (IsA(arg, NamedArgExpr))
			argnames = lappend(argnames, ((NamedArgExpr *) arg)->name);
		argtypes[nargs] = exprType(arg);
		nargs++;
	}

	appendStringInfo(buf, "%s(",
					 generate_function_name(funcoid, nargs,
											argnames, argtypes,
											&is_variadic));
	nargs = 0;
	foreach(l, expr->args)
	{
		if (nargs++ > 0)
			appendStringInfoString(buf, ", ");
		if (is_variadic && lnext(l) == NULL)
			appendStringInfoString(buf, "VARIADIC ");
		get_rule_expr((Node *) lfirst(l), context, true);
	}
	appendStringInfoChar(buf, ')');
}

/*
 * get_agg_expr			- Parse back an Aggref node
 */
static void
get_agg_expr(Aggref *aggref, deparse_context *context)
{
	StringInfo	buf = context->buf;
	Oid			argtypes[FUNC_MAX_ARGS];
	List	   *arglist;
	int			nargs;
	ListCell   *l;
#ifdef PGXC
	bool		added_finalfn = false;
#endif /* PGXC */

	/* Extract the regular arguments, ignoring resjunk stuff for the moment */
	arglist = NIL;
	nargs = 0;
	foreach(l, aggref->args)
	{
		TargetEntry *tle = (TargetEntry *) lfirst(l);
		Node	   *arg = (Node *) tle->expr;

		Assert(!IsA(arg, NamedArgExpr));
		if (tle->resjunk)
			continue;
		if (nargs >= FUNC_MAX_ARGS)		/* paranoia */
			ereport(ERROR,
					(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
					 errmsg("too many arguments")));
		argtypes[nargs] = exprType(arg);
		arglist = lappend(arglist, arg);
		nargs++;
	}

#ifdef PGXC
	/*
	 * Datanode should send finalised aggregate results. Datanodes evaluate only
	 * transition results. In order to get the finalised aggregate, we enclose
	 * the aggregate call inside final function call, so as to get finalised
	 * results at the Coordinator
	 */
	if (context->finalise_aggs)
	{
		HeapTuple			aggTuple;
		Form_pg_aggregate	aggform;
		aggTuple = SearchSysCache(AGGFNOID,
						  ObjectIdGetDatum(aggref->aggfnoid),
						  0, 0, 0);
		if (!HeapTupleIsValid(aggTuple))
			elog(ERROR, "cache lookup failed for aggregate %u",
				 aggref->aggfnoid);
		aggform = (Form_pg_aggregate) GETSTRUCT(aggTuple);

		if (OidIsValid(aggform->aggfinalfn))
		{
			appendStringInfo(buf, "%s(", generate_function_name(aggform->aggfinalfn, 0,
													NULL, NULL, NULL));
			added_finalfn = true;
		}
		ReleaseSysCache(aggTuple);
	}
#endif /* PGXC */

	appendStringInfo(buf, "%s(%s",
					 generate_function_name(aggref->aggfnoid, nargs,
											NIL, argtypes, NULL),
					 (aggref->aggdistinct != NIL) ? "DISTINCT " : "");
	/* aggstar can be set only in zero-argument aggregates */
	if (aggref->aggstar)
		appendStringInfoChar(buf, '*');
	else
		get_rule_expr((Node *) arglist, context, true);
	if (aggref->aggorder != NIL)
	{
		appendStringInfoString(buf, " ORDER BY ");
		get_rule_orderby(aggref->aggorder, aggref->args, false, context);
	}
	appendStringInfoChar(buf, ')');

#ifdef PGXC
	if (added_finalfn)
		appendStringInfoChar(buf, ')');
#endif /* PGXC */
}

/*
 * get_windowfunc_expr	- Parse back a WindowFunc node
 */
static void
get_windowfunc_expr(WindowFunc *wfunc, deparse_context *context)
{
	StringInfo	buf = context->buf;
	Oid			argtypes[FUNC_MAX_ARGS];
	int			nargs;
	ListCell   *l;

	if (list_length(wfunc->args) > FUNC_MAX_ARGS)
		ereport(ERROR,
				(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
				 errmsg("too many arguments")));
	nargs = 0;
	foreach(l, wfunc->args)
	{
		Node	   *arg = (Node *) lfirst(l);

		Assert(!IsA(arg, NamedArgExpr));
		argtypes[nargs] = exprType(arg);
		nargs++;
	}

	appendStringInfo(buf, "%s(",
					 generate_function_name(wfunc->winfnoid, nargs,
											NIL, argtypes, NULL));
	/* winstar can be set only in zero-argument aggregates */
	if (wfunc->winstar)
		appendStringInfoChar(buf, '*');
	else
		get_rule_expr((Node *) wfunc->args, context, true);
	appendStringInfoString(buf, ") OVER ");

	foreach(l, context->windowClause)
	{
		WindowClause *wc = (WindowClause *) lfirst(l);

		if (wc->winref == wfunc->winref)
		{
			if (wc->name)
				appendStringInfoString(buf, quote_identifier(wc->name));
			else
				get_rule_windowspec(wc, context->windowTList, context);
			break;
		}
	}
	if (l == NULL)
	{
		if (context->windowClause)
			elog(ERROR, "could not find window clause for winref %u",
				 wfunc->winref);

		/*
		 * In EXPLAIN, we don't have window context information available, so
		 * we have to settle for this:
		 */
		appendStringInfoString(buf, "(?)");
	}
}

/* ----------
 * get_coercion_expr
 *
 *	Make a string representation of a value coerced to a specific type
 * ----------
 */
static void
get_coercion_expr(Node *arg, deparse_context *context,
				  Oid resulttype, int32 resulttypmod,
				  Node *parentNode)
{
	StringInfo	buf = context->buf;

	/*
	 * Since parse_coerce.c doesn't immediately collapse application of
	 * length-coercion functions to constants, what we'll typically see in
	 * such cases is a Const with typmod -1 and a length-coercion function
	 * right above it.	Avoid generating redundant output. However, beware of
	 * suppressing casts when the user actually wrote something like
	 * 'foo'::text::char(3).
	 */
	if (arg && IsA(arg, Const) &&
		((Const *) arg)->consttype == resulttype &&
		((Const *) arg)->consttypmod == -1)
	{
		/* Show the constant without normal ::typename decoration */
		get_const_expr((Const *) arg, context, -1);
	}
	else
	{
		if (!PRETTY_PAREN(context))
			appendStringInfoChar(buf, '(');
		get_rule_expr_paren(arg, context, false, parentNode);
		if (!PRETTY_PAREN(context))
			appendStringInfoChar(buf, ')');
	}
	appendStringInfo(buf, "::%s",
					 format_type_with_typemod(resulttype, resulttypmod));
}

/* ----------
 * get_const_expr
 *
 *	Make a string representation of a Const
 *
 * showtype can be -1 to never show "::typename" decoration, or +1 to always
 * show it, or 0 to show it only if the constant wouldn't be assumed to be
 * the right type by default.
 *
 * If the Const's collation isn't default for its type, show that too.
 * This can only happen in trees that have been through constant-folding.
 * We assume we don't need to do this when showtype is -1.
 * ----------
 */
static void
get_const_expr(Const *constval, deparse_context *context, int showtype)
{
	StringInfo	buf = context->buf;
	Oid			typoutput;
	bool		typIsVarlena;
	char	   *extval;
	bool		isfloat = false;
	bool		needlabel;

	if (constval->constisnull)
	{
		/*
		 * Always label the type of a NULL constant to prevent misdecisions
		 * about type when reparsing.
		 */
		appendStringInfo(buf, "NULL");
		if (showtype >= 0)
		{
			appendStringInfo(buf, "::%s",
							 format_type_with_typemod(constval->consttype,
													  constval->consttypmod));
			get_const_collation(constval, context);
		}
		return;
	}

	getTypeOutputInfo(constval->consttype,
					  &typoutput, &typIsVarlena);

	extval = OidOutputFunctionCall(typoutput, constval->constvalue);

	switch (constval->consttype)
	{
		case INT2OID:
		case INT4OID:
		case INT8OID:
		case OIDOID:
		case FLOAT4OID:
		case FLOAT8OID:
		case NUMERICOID:
			{
				/*
				 * These types are printed without quotes unless they contain
				 * values that aren't accepted by the scanner unquoted (e.g.,
				 * 'NaN').	Note that strtod() and friends might accept NaN,
				 * so we can't use that to test.
				 *
				 * In reality we only need to defend against infinity and NaN,
				 * so we need not get too crazy about pattern matching here.
				 *
				 * There is a special-case gotcha: if the constant is signed,
				 * we need to parenthesize it, else the parser might see a
				 * leading plus/minus as binding less tightly than adjacent
				 * operators --- particularly, the cast that we might attach
				 * below.
				 */
				if (strspn(extval, "0123456789+-eE.") == strlen(extval))
				{
					if (extval[0] == '+' || extval[0] == '-')
						appendStringInfo(buf, "(%s)", extval);
					else
						appendStringInfoString(buf, extval);
					if (strcspn(extval, "eE.") != strlen(extval))
						isfloat = true; /* it looks like a float */
				}
				else
					appendStringInfo(buf, "'%s'", extval);
			}
			break;

		case BITOID:
		case VARBITOID:
			appendStringInfo(buf, "B'%s'", extval);
			break;

		case BOOLOID:
			if (strcmp(extval, "t") == 0)
				appendStringInfo(buf, "true");
			else
				appendStringInfo(buf, "false");
			break;

		default:
			simple_quote_literal(buf, extval);
			break;
	}

	pfree(extval);

	if (showtype < 0)
		return;

	/*
	 * For showtype == 0, append ::typename unless the constant will be
	 * implicitly typed as the right type when it is read in.
	 *
	 * XXX this code has to be kept in sync with the behavior of the parser,
	 * especially make_const.
	 */
	switch (constval->consttype)
	{
		case BOOLOID:
		case INT4OID:
		case UNKNOWNOID:
			/* These types can be left unlabeled */
			needlabel = false;
			break;
		case NUMERICOID:

			/*
			 * Float-looking constants will be typed as numeric, but if
			 * there's a specific typmod we need to show it.
			 */
			needlabel = !isfloat || (constval->consttypmod >= 0);
			break;
		default:
			needlabel = true;
			break;
	}
	if (needlabel || showtype > 0)
		appendStringInfo(buf, "::%s",
						 format_type_with_typemod(constval->consttype,
												  constval->consttypmod));

	get_const_collation(constval, context);
}

/*
 * helper for get_const_expr: append COLLATE if needed
 */
static void
get_const_collation(Const *constval, deparse_context *context)
{
	StringInfo	buf = context->buf;

	if (OidIsValid(constval->constcollid))
	{
		Oid			typcollation = get_typcollation(constval->consttype);

		if (constval->constcollid != typcollation)
		{
			appendStringInfo(buf, " COLLATE %s",
							 generate_collation_name(constval->constcollid));
		}
	}
}

/*
 * simple_quote_literal - Format a string as a SQL literal, append to buf
 */
static void
simple_quote_literal(StringInfo buf, const char *val)
{
	const char *valptr;

	/*
	 * We form the string literal according to the prevailing setting of
	 * standard_conforming_strings; we never use E''. User is responsible for
	 * making sure result is used correctly.
	 */
	appendStringInfoChar(buf, '\'');
	for (valptr = val; *valptr; valptr++)
	{
		char		ch = *valptr;

		if (SQL_STR_DOUBLE(ch, !standard_conforming_strings))
			appendStringInfoChar(buf, ch);
		appendStringInfoChar(buf, ch);
	}
	appendStringInfoChar(buf, '\'');
}


/* ----------
 * get_sublink_expr			- Parse back a sublink
 * ----------
 */
static void
get_sublink_expr(SubLink *sublink, deparse_context *context)
{
	StringInfo	buf = context->buf;
	Query	   *query = (Query *) (sublink->subselect);
	char	   *opname = NULL;
	bool		need_paren;

	if (sublink->subLinkType == ARRAY_SUBLINK)
		appendStringInfo(buf, "ARRAY(");
	else
		appendStringInfoChar(buf, '(');

	/*
	 * Note that we print the name of only the first operator, when there are
	 * multiple combining operators.  This is an approximation that could go
	 * wrong in various scenarios (operators in different schemas, renamed
	 * operators, etc) but there is not a whole lot we can do about it, since
	 * the syntax allows only one operator to be shown.
	 */
	if (sublink->testexpr)
	{
		if (IsA(sublink->testexpr, OpExpr))
		{
			/* single combining operator */
			OpExpr	   *opexpr = (OpExpr *) sublink->testexpr;

			get_rule_expr(linitial(opexpr->args), context, true);
			opname = generate_operator_name(opexpr->opno,
											exprType(linitial(opexpr->args)),
											exprType(lsecond(opexpr->args)));
		}
		else if (IsA(sublink->testexpr, BoolExpr))
		{
			/* multiple combining operators, = or <> cases */
			char	   *sep;
			ListCell   *l;

			appendStringInfoChar(buf, '(');
			sep = "";
			foreach(l, ((BoolExpr *) sublink->testexpr)->args)
			{
				OpExpr	   *opexpr = (OpExpr *) lfirst(l);

				Assert(IsA(opexpr, OpExpr));
				appendStringInfoString(buf, sep);
				get_rule_expr(linitial(opexpr->args), context, true);
				if (!opname)
					opname = generate_operator_name(opexpr->opno,
											exprType(linitial(opexpr->args)),
											exprType(lsecond(opexpr->args)));
				sep = ", ";
			}
			appendStringInfoChar(buf, ')');
		}
		else if (IsA(sublink->testexpr, RowCompareExpr))
		{
			/* multiple combining operators, < <= > >= cases */
			RowCompareExpr *rcexpr = (RowCompareExpr *) sublink->testexpr;

			appendStringInfoChar(buf, '(');
			get_rule_expr((Node *) rcexpr->largs, context, true);
			opname = generate_operator_name(linitial_oid(rcexpr->opnos),
											exprType(linitial(rcexpr->largs)),
										  exprType(linitial(rcexpr->rargs)));
			appendStringInfoChar(buf, ')');
		}
		else
			elog(ERROR, "unrecognized testexpr type: %d",
				 (int) nodeTag(sublink->testexpr));
	}

	need_paren = true;

	switch (sublink->subLinkType)
	{
		case EXISTS_SUBLINK:
			appendStringInfo(buf, "EXISTS ");
			break;

		case ANY_SUBLINK:
			if (strcmp(opname, "=") == 0)		/* Represent = ANY as IN */
				appendStringInfo(buf, " IN ");
			else
				appendStringInfo(buf, " %s ANY ", opname);
			break;

		case ALL_SUBLINK:
			appendStringInfo(buf, " %s ALL ", opname);
			break;

		case ROWCOMPARE_SUBLINK:
			appendStringInfo(buf, " %s ", opname);
			break;

		case EXPR_SUBLINK:
		case ARRAY_SUBLINK:
			need_paren = false;
			break;

		case CTE_SUBLINK:		/* shouldn't occur in a SubLink */
		default:
			elog(ERROR, "unrecognized sublink type: %d",
				 (int) sublink->subLinkType);
			break;
	}

	if (need_paren)
		appendStringInfoChar(buf, '(');

	get_query_def(query, buf, context->namespaces, NULL,
				  context->prettyFlags, context->wrapColumn,
				  context->indentLevel
#ifdef PGXC
				  , context->finalise_aggs, context->sortgroup_colno
#endif /* PGXC */
				  );

	if (need_paren)
		appendStringInfo(buf, "))");
	else
		appendStringInfoChar(buf, ')');
}


/* ----------
 * get_from_clause			- Parse back a FROM clause
 *
 * "prefix" is the keyword that denotes the start of the list of FROM
 * elements. It is FROM when used to parse back SELECT and UPDATE, but
 * is USING when parsing back DELETE.
 * ----------
 */
static void
get_from_clause(Query *query, const char *prefix, deparse_context *context)
{
	StringInfo	buf = context->buf;
	bool		first = true;
	ListCell   *l;

	/*
	 * We use the query's jointree as a guide to what to print.  However, we
	 * must ignore auto-added RTEs that are marked not inFromCl. (These can
	 * only appear at the top level of the jointree, so it's sufficient to
	 * check here.)  This check also ensures we ignore the rule pseudo-RTEs
	 * for NEW and OLD.
	 */
	foreach(l, query->jointree->fromlist)
	{
		Node	   *jtnode = (Node *) lfirst(l);

		if (IsA(jtnode, RangeTblRef))
		{
			int			varno = ((RangeTblRef *) jtnode)->rtindex;
			RangeTblEntry *rte = rt_fetch(varno, query->rtable);

			if (!rte->inFromCl)
				continue;
		}

		if (first)
		{
			appendContextKeyword(context, prefix,
								 -PRETTYINDENT_STD, PRETTYINDENT_STD, 2);
			first = false;

			get_from_clause_item(jtnode, query, context);
		}
		else
		{
			StringInfoData itembuf;

			appendStringInfoString(buf, ", ");

			/*
			 * Put the new FROM item's text into itembuf so we can decide
			 * after we've got it whether or not it needs to go on a new line.
			 */
			initStringInfo(&itembuf);
			context->buf = &itembuf;

			get_from_clause_item(jtnode, query, context);

			/* Restore context's output buffer */
			context->buf = buf;

			/* Consider line-wrapping if enabled */
			if (PRETTY_INDENT(context) && context->wrapColumn >= 0)
			{
				char	   *trailing_nl;

				/* Locate the start of the current line in the buffer */
				trailing_nl = strrchr(buf->data, '\n');
				if (trailing_nl == NULL)
					trailing_nl = buf->data;
				else
					trailing_nl++;

				/*
				 * Add a newline, plus some indentation, if the new item would
				 * cause an overflow.
				 */
				if (strlen(trailing_nl) + strlen(itembuf.data) > context->wrapColumn)
					appendContextKeyword(context, "", -PRETTYINDENT_STD,
										 PRETTYINDENT_STD, PRETTYINDENT_VAR);
			}

			/* Add the new item */
			appendStringInfoString(buf, itembuf.data);

			/* clean up */
			pfree(itembuf.data);
		}
	}
}

static void
get_from_clause_item(Node *jtnode, Query *query, deparse_context *context)
{
	StringInfo	buf = context->buf;

	if (IsA(jtnode, RangeTblRef))
	{
		int			varno = ((RangeTblRef *) jtnode)->rtindex;
		RangeTblEntry *rte = rt_fetch(varno, query->rtable);
		bool		gavealias = false;

		switch (rte->rtekind)
		{
			case RTE_RELATION:
				/* Normal relation RTE */
				appendStringInfo(buf, "%s%s",
								 only_marker(rte),
								 generate_relation_name(rte->relid,
														context->namespaces));
				break;
			case RTE_SUBQUERY:
				/* Subquery RTE */
				appendStringInfoChar(buf, '(');
				get_query_def(rte->subquery, buf, context->namespaces, NULL,
							  context->prettyFlags, context->wrapColumn,
							  context->indentLevel
#ifdef PGXC
							  , context->finalise_aggs, context->sortgroup_colno
#endif /* PGXC */
							  );
				appendStringInfoChar(buf, ')');
				break;
			case RTE_FUNCTION:
				/* Function RTE */
				get_rule_expr(rte->funcexpr, context, true);
				break;
			case RTE_VALUES:
				/* Values list RTE */
				get_values_def(rte->values_lists, context);
				break;
			case RTE_CTE:
				appendStringInfoString(buf, quote_identifier(rte->ctename));
				break;
			default:
				elog(ERROR, "unrecognized RTE kind: %d", (int) rte->rtekind);
				break;
		}

		if (rte->alias != NULL)
		{
			appendStringInfo(buf, " %s",
							 quote_identifier(rte->alias->aliasname));
			gavealias = true;
		}
		else if (rte->rtekind == RTE_RELATION &&
			strcmp(rte->eref->aliasname, get_relation_name(rte->relid)) != 0)
		{
			/*
			 * Apparently the rel has been renamed since the rule was made.
			 * Emit a fake alias clause so that variable references will still
			 * work.  This is not a 100% solution but should work in most
			 * reasonable situations.
			 */
			appendStringInfo(buf, " %s",
							 quote_identifier(rte->eref->aliasname));
			gavealias = true;
		}
#ifdef PGXC
		else if (rte->rtekind == RTE_SUBQUERY && rte->eref->aliasname)
		{
			/*
			 *
			 * This condition arises when the from clause is a view. The
			 * corresponding subquery RTE has its eref set to view name.
			 * The remote query generated has this subquery of which the
			 * columns can be referred to as view_name.col1, so it should
			 * be possible to refer to this subquery object.
			 */
			appendStringInfo(buf, " %s",
							 quote_identifier(rte->eref->aliasname));
			gavealias = true;
		}
#endif
		else if (rte->rtekind == RTE_FUNCTION)
		{
			/*
			 * For a function RTE, always give an alias. This covers possible
			 * renaming of the function and/or instability of the
			 * FigureColname rules for things that aren't simple functions.
			 */
			appendStringInfo(buf, " %s",
							 quote_identifier(rte->eref->aliasname));
			gavealias = true;
		}

		if (rte->rtekind == RTE_FUNCTION)
		{
			if (rte->funccoltypes != NIL)
			{
				/* Function returning RECORD, reconstruct the columndefs */
				if (!gavealias)
					appendStringInfo(buf, " AS ");
				get_from_clause_coldeflist(rte->eref->colnames,
										   rte->funccoltypes,
										   rte->funccoltypmods,
										   rte->funccolcollations,
										   context);
			}
			else
			{
				/*
				 * For a function RTE, always emit a complete column alias
				 * list; this is to protect against possible instability of
				 * the default column names (eg, from altering parameter
				 * names).
				 */
				get_from_clause_alias(rte->eref, rte, context);
			}
		}
		else
		{
			/*
			 * For non-function RTEs, just report whatever the user originally
			 * gave as column aliases.
			 */
			get_from_clause_alias(rte->alias, rte, context);
		}
	}
	else if (IsA(jtnode, JoinExpr))
	{
		JoinExpr   *j = (JoinExpr *) jtnode;
		bool		need_paren_on_right;

		need_paren_on_right = PRETTY_PAREN(context) &&
			!IsA(j->rarg, RangeTblRef) &&
			!(IsA(j->rarg, JoinExpr) &&((JoinExpr *) j->rarg)->alias != NULL);

		if (!PRETTY_PAREN(context) || j->alias != NULL)
			appendStringInfoChar(buf, '(');

		get_from_clause_item(j->larg, query, context);

		if (j->isNatural)
		{
			if (!PRETTY_INDENT(context))
				appendStringInfoChar(buf, ' ');
			switch (j->jointype)
			{
				case JOIN_INNER:
					appendContextKeyword(context, "NATURAL JOIN ",
										 -PRETTYINDENT_JOIN,
										 PRETTYINDENT_JOIN, 0);
					break;
				case JOIN_LEFT:
					appendContextKeyword(context, "NATURAL LEFT JOIN ",
										 -PRETTYINDENT_JOIN,
										 PRETTYINDENT_JOIN, 0);
					break;
				case JOIN_FULL:
					appendContextKeyword(context, "NATURAL FULL JOIN ",
										 -PRETTYINDENT_JOIN,
										 PRETTYINDENT_JOIN, 0);
					break;
				case JOIN_RIGHT:
					appendContextKeyword(context, "NATURAL RIGHT JOIN ",
										 -PRETTYINDENT_JOIN,
										 PRETTYINDENT_JOIN, 0);
					break;
				default:
					elog(ERROR, "unrecognized join type: %d",
						 (int) j->jointype);
			}
		}
		else
		{
			switch (j->jointype)
			{
				case JOIN_INNER:
					if (j->quals)
						appendContextKeyword(context, " JOIN ",
											 -PRETTYINDENT_JOIN,
											 PRETTYINDENT_JOIN, 2);
					else
						appendContextKeyword(context, " CROSS JOIN ",
											 -PRETTYINDENT_JOIN,
											 PRETTYINDENT_JOIN, 1);
					break;
				case JOIN_LEFT:
					appendContextKeyword(context, " LEFT JOIN ",
										 -PRETTYINDENT_JOIN,
										 PRETTYINDENT_JOIN, 2);
					break;
				case JOIN_FULL:
					appendContextKeyword(context, " FULL JOIN ",
										 -PRETTYINDENT_JOIN,
										 PRETTYINDENT_JOIN, 2);
					break;
				case JOIN_RIGHT:
					appendContextKeyword(context, " RIGHT JOIN ",
										 -PRETTYINDENT_JOIN,
										 PRETTYINDENT_JOIN, 2);
					break;
				default:
					elog(ERROR, "unrecognized join type: %d",
						 (int) j->jointype);
			}
		}

		if (need_paren_on_right)
			appendStringInfoChar(buf, '(');
		get_from_clause_item(j->rarg, query, context);
		if (need_paren_on_right)
			appendStringInfoChar(buf, ')');

		context->indentLevel -= PRETTYINDENT_JOIN_ON;

		if (!j->isNatural)
		{
			if (j->usingClause)
			{
				ListCell   *col;

				appendStringInfo(buf, " USING (");
				foreach(col, j->usingClause)
				{
					if (col != list_head(j->usingClause))
						appendStringInfo(buf, ", ");
					appendStringInfoString(buf,
									  quote_identifier(strVal(lfirst(col))));
				}
				appendStringInfoChar(buf, ')');
			}
			else if (j->quals)
			{
				appendStringInfo(buf, " ON ");
				if (!PRETTY_PAREN(context))
					appendStringInfoChar(buf, '(');
				get_rule_expr(j->quals, context, false);
				if (!PRETTY_PAREN(context))
					appendStringInfoChar(buf, ')');
			}
		}
		if (!PRETTY_PAREN(context) || j->alias != NULL)
			appendStringInfoChar(buf, ')');

		/* Yes, it's correct to put alias after the right paren ... */
		if (j->alias != NULL)
		{
			appendStringInfo(buf, " %s",
							 quote_identifier(j->alias->aliasname));
			get_from_clause_alias(j->alias,
								  rt_fetch(j->rtindex, query->rtable),
								  context);
		}
	}
	else
		elog(ERROR, "unrecognized node type: %d",
			 (int) nodeTag(jtnode));
}

/*
 * get_from_clause_alias - reproduce column alias list
 *
 * This is tricky because we must ignore dropped columns.
 */
static void
get_from_clause_alias(Alias *alias, RangeTblEntry *rte,
					  deparse_context *context)
{
	StringInfo	buf = context->buf;
	ListCell   *col;
	AttrNumber	attnum;
	bool		first = true;

	if (alias == NULL || alias->colnames == NIL)
		return;					/* definitely nothing to do */

	attnum = 0;
	foreach(col, alias->colnames)
	{
		attnum++;
		if (get_rte_attribute_is_dropped(rte, attnum))
			continue;
		if (first)
		{
			appendStringInfoChar(buf, '(');
			first = false;
		}
		else
			appendStringInfo(buf, ", ");
		appendStringInfoString(buf,
							   quote_identifier(strVal(lfirst(col))));
	}
	if (!first)
		appendStringInfoChar(buf, ')');
}

/*
 * get_from_clause_coldeflist - reproduce FROM clause coldeflist
 *
 * The coldeflist is appended immediately (no space) to buf.  Caller is
 * responsible for ensuring that an alias or AS is present before it.
 */
static void
get_from_clause_coldeflist(List *names,
						   List *types, List *typmods, List *collations,
						   deparse_context *context)
{
	StringInfo	buf = context->buf;
	ListCell   *l1;
	ListCell   *l2;
	ListCell   *l3;
	ListCell   *l4;
	int			i = 0;

	appendStringInfoChar(buf, '(');

	l2 = list_head(types);
	l3 = list_head(typmods);
	l4 = list_head(collations);
	foreach(l1, names)
	{
		char	   *attname = strVal(lfirst(l1));
		Oid			atttypid;
		int32		atttypmod;
		Oid			attcollation;

		atttypid = lfirst_oid(l2);
		l2 = lnext(l2);
		atttypmod = lfirst_int(l3);
		l3 = lnext(l3);
		attcollation = lfirst_oid(l4);
		l4 = lnext(l4);

		if (i > 0)
			appendStringInfo(buf, ", ");
		appendStringInfo(buf, "%s %s",
						 quote_identifier(attname),
						 format_type_with_typemod(atttypid, atttypmod));
		if (OidIsValid(attcollation) &&
			attcollation != get_typcollation(atttypid))
			appendStringInfo(buf, " COLLATE %s",
							 generate_collation_name(attcollation));
		i++;
	}

	appendStringInfoChar(buf, ')');
}

/*
 * get_opclass_name			- fetch name of an index operator class
 *
 * The opclass name is appended (after a space) to buf.
 *
 * Output is suppressed if the opclass is the default for the given
 * actual_datatype.  (If you don't want this behavior, just pass
 * InvalidOid for actual_datatype.)
 */
static void
get_opclass_name(Oid opclass, Oid actual_datatype,
				 StringInfo buf)
{
	HeapTuple	ht_opc;
	Form_pg_opclass opcrec;
	char	   *opcname;
	char	   *nspname;

	ht_opc = SearchSysCache1(CLAOID, ObjectIdGetDatum(opclass));
	if (!HeapTupleIsValid(ht_opc))
		elog(ERROR, "cache lookup failed for opclass %u", opclass);
	opcrec = (Form_pg_opclass) GETSTRUCT(ht_opc);

	if (!OidIsValid(actual_datatype) ||
		GetDefaultOpClass(actual_datatype, opcrec->opcmethod) != opclass)
	{
		/* Okay, we need the opclass name.	Do we need to qualify it? */
		opcname = NameStr(opcrec->opcname);
		if (OpclassIsVisible(opclass))
			appendStringInfo(buf, " %s", quote_identifier(opcname));
		else
		{
			nspname = get_namespace_name(opcrec->opcnamespace);
			appendStringInfo(buf, " %s.%s",
							 quote_identifier(nspname),
							 quote_identifier(opcname));
		}
	}
	ReleaseSysCache(ht_opc);
}

/*
 * processIndirection - take care of array and subfield assignment
 *
 * We strip any top-level FieldStore or assignment ArrayRef nodes that
 * appear in the input, and return the subexpression that's to be assigned.
 * If printit is true, we also print out the appropriate decoration for the
 * base column name (that the caller just printed).
 */
static Node *
processIndirection(Node *node, deparse_context *context, bool printit)
{
	StringInfo	buf = context->buf;

	for (;;)
	{
		if (node == NULL)
			break;
		if (IsA(node, FieldStore))
		{
			FieldStore *fstore = (FieldStore *) node;
			Oid			typrelid;
			char	   *fieldname;

			/* lookup tuple type */
			typrelid = get_typ_typrelid(fstore->resulttype);
			if (!OidIsValid(typrelid))
				elog(ERROR, "argument type %s of FieldStore is not a tuple type",
					 format_type_be(fstore->resulttype));

			/*
			 * Print the field name.  There should only be one target field in
			 * stored rules.  There could be more than that in executable
			 * target lists, but this function cannot be used for that case.
			 */
			Assert(list_length(fstore->fieldnums) == 1);
			fieldname = get_relid_attribute_name(typrelid,
											linitial_int(fstore->fieldnums));
			if (printit)
				appendStringInfo(buf, ".%s", quote_identifier(fieldname));

			/*
			 * We ignore arg since it should be an uninteresting reference to
			 * the target column or subcolumn.
			 */
			node = (Node *) linitial(fstore->newvals);
		}
		else if (IsA(node, ArrayRef))
		{
			ArrayRef   *aref = (ArrayRef *) node;

			if (aref->refassgnexpr == NULL)
				break;
			if (printit)
				printSubscripts(aref, context);

			/*
			 * We ignore refexpr since it should be an uninteresting reference
			 * to the target column or subcolumn.
			 */
			node = (Node *) aref->refassgnexpr;
		}
		else
			break;
	}

	return node;
}

static void
printSubscripts(ArrayRef *aref, deparse_context *context)
{
	StringInfo	buf = context->buf;
	ListCell   *lowlist_item;
	ListCell   *uplist_item;

	lowlist_item = list_head(aref->reflowerindexpr);	/* could be NULL */
	foreach(uplist_item, aref->refupperindexpr)
	{
		appendStringInfoChar(buf, '[');
		if (lowlist_item)
		{
			get_rule_expr((Node *) lfirst(lowlist_item), context, false);
			appendStringInfoChar(buf, ':');
			lowlist_item = lnext(lowlist_item);
		}
		get_rule_expr((Node *) lfirst(uplist_item), context, false);
		appendStringInfoChar(buf, ']');
	}
}

/*
 * quote_identifier			- Quote an identifier only if needed
 *
 * When quotes are needed, we palloc the required space; slightly
 * space-wasteful but well worth it for notational simplicity.
 */
const char *
quote_identifier(const char *ident)
{
	/*
	 * Can avoid quoting if ident starts with a lowercase letter or underscore
	 * and contains only lowercase letters, digits, and underscores, *and* is
	 * not any SQL keyword.  Otherwise, supply quotes.
	 */
	int			nquotes = 0;
	bool		safe;
	const char *ptr;
	char	   *result;
	char	   *optr;

	/*
	 * would like to use <ctype.h> macros here, but they might yield unwanted
	 * locale-specific results...
	 */
	safe = ((ident[0] >= 'a' && ident[0] <= 'z') || ident[0] == '_');

	for (ptr = ident; *ptr; ptr++)
	{
		char		ch = *ptr;

		if ((ch >= 'a' && ch <= 'z') ||
			(ch >= '0' && ch <= '9') ||
			(ch == '_'))
		{
			/* okay */
		}
		else
		{
			safe = false;
			if (ch == '"')
				nquotes++;
		}
	}

	if (quote_all_identifiers)
		safe = false;

	if (safe)
	{
		/*
		 * Check for keyword.  We quote keywords except for unreserved ones.
		 * (In some cases we could avoid quoting a col_name or type_func_name
		 * keyword, but it seems much harder than it's worth to tell that.)
		 *
		 * Note: ScanKeywordLookup() does case-insensitive comparison, but
		 * that's fine, since we already know we have all-lower-case.
		 */
		const ScanKeyword *keyword = ScanKeywordLookup(ident,
													   ScanKeywords,
													   NumScanKeywords);

		if (keyword != NULL && keyword->category != UNRESERVED_KEYWORD)
			safe = false;
	}

	if (safe)
		return ident;			/* no change needed */

	result = (char *) palloc(strlen(ident) + nquotes + 2 + 1);

	optr = result;
	*optr++ = '"';
	for (ptr = ident; *ptr; ptr++)
	{
		char		ch = *ptr;

		if (ch == '"')
			*optr++ = '"';
		*optr++ = ch;
	}
	*optr++ = '"';
	*optr = '\0';

	return result;
}

/*
 * quote_qualified_identifier	- Quote a possibly-qualified identifier
 *
 * Return a name of the form qualifier.ident, or just ident if qualifier
 * is NULL, quoting each component if necessary.  The result is palloc'd.
 */
char *
quote_qualified_identifier(const char *qualifier,
						   const char *ident)
{
	StringInfoData buf;

	initStringInfo(&buf);
	if (qualifier)
		appendStringInfo(&buf, "%s.", quote_identifier(qualifier));
	appendStringInfoString(&buf, quote_identifier(ident));
	return buf.data;
}

/*
 * get_relation_name
 *		Get the unqualified name of a relation specified by OID
 *
 * This differs from the underlying get_rel_name() function in that it will
 * throw error instead of silently returning NULL if the OID is bad.
 */
static char *
get_relation_name(Oid relid)
{
	char	   *relname = get_rel_name(relid);

	if (!relname)
		elog(ERROR, "cache lookup failed for relation %u", relid);
	return relname;
}

/*
 * generate_relation_name
 *		Compute the name to display for a relation specified by OID
 *
 * The result includes all necessary quoting and schema-prefixing.
 *
 * If namespaces isn't NIL, it must be a list of deparse_namespace nodes.
 * We will forcibly qualify the relation name if it equals any CTE name
 * visible in the namespace list.
 */
static char *
generate_relation_name(Oid relid, List *namespaces)
{
	HeapTuple	tp;
	Form_pg_class reltup;
	bool		need_qual;
	ListCell   *nslist;
	char	   *relname;
	char	   *nspname;
	char	   *result;

	tp = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
	if (!HeapTupleIsValid(tp))
		elog(ERROR, "cache lookup failed for relation %u", relid);
	reltup = (Form_pg_class) GETSTRUCT(tp);
	relname = NameStr(reltup->relname);

	/* Check for conflicting CTE name */
	need_qual = false;
	foreach(nslist, namespaces)
	{
		deparse_namespace *dpns = (deparse_namespace *) lfirst(nslist);
		ListCell   *ctlist;

		foreach(ctlist, dpns->ctes)
		{
			CommonTableExpr *cte = (CommonTableExpr *) lfirst(ctlist);

			if (strcmp(cte->ctename, relname) == 0)
			{
				need_qual = true;
				break;
			}
		}
		if (need_qual)
			break;
	}

	/* Otherwise, qualify the name if not visible in search path */
	if (!need_qual)
		need_qual = !RelationIsVisible(relid);

	if (need_qual)
		nspname = get_namespace_name(reltup->relnamespace);
	else
		nspname = NULL;

	result = quote_qualified_identifier(nspname, relname);

	ReleaseSysCache(tp);

	return result;
}

/*
 * generate_function_name
 *		Compute the name to display for a function specified by OID,
 *		given that it is being called with the specified actual arg names and
 *		types.	(Those matter because of ambiguous-function resolution rules.)
 *
 * The result includes all necessary quoting and schema-prefixing.	We can
 * also pass back an indication of whether the function is variadic.
 */
static char *
generate_function_name(Oid funcid, int nargs, List *argnames,
					   Oid *argtypes, bool *is_variadic)
{
	HeapTuple	proctup;
	Form_pg_proc procform;
	char	   *proname;
	char	   *nspname;
	char	   *result;
	FuncDetailCode p_result;
	Oid			p_funcid;
	Oid			p_rettype;
	bool		p_retset;
	int			p_nvargs;
	Oid		   *p_true_typeids;

	proctup = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
	if (!HeapTupleIsValid(proctup))
		elog(ERROR, "cache lookup failed for function %u", funcid);
	procform = (Form_pg_proc) GETSTRUCT(proctup);
	proname = NameStr(procform->proname);

	/*
	 * The idea here is to schema-qualify only if the parser would fail to
	 * resolve the correct function given the unqualified func name with the
	 * specified argtypes.	If the function is variadic, we should presume
	 * that VARIADIC will be included in the call.
	 */
	p_result = func_get_detail(list_make1(makeString(proname)),
							   NIL, argnames, nargs, argtypes,
							   !OidIsValid(procform->provariadic), true,
							   &p_funcid, &p_rettype,
							   &p_retset, &p_nvargs, &p_true_typeids, NULL);
	if ((p_result == FUNCDETAIL_NORMAL ||
		 p_result == FUNCDETAIL_AGGREGATE ||
		 p_result == FUNCDETAIL_WINDOWFUNC) &&
		p_funcid == funcid)
		nspname = NULL;
	else
		nspname = get_namespace_name(procform->pronamespace);

	result = quote_qualified_identifier(nspname, proname);

	/* Check variadic-ness if caller cares */
	if (is_variadic)
	{
		/* "any" variadics are not treated as variadics for listing */
		if (OidIsValid(procform->provariadic) &&
			procform->provariadic != ANYOID)
			*is_variadic = true;
		else
			*is_variadic = false;
	}

	ReleaseSysCache(proctup);

	return result;
}

/*
 * generate_operator_name
 *		Compute the name to display for an operator specified by OID,
 *		given that it is being called with the specified actual arg types.
 *		(Arg types matter because of ambiguous-operator resolution rules.
 *		Pass InvalidOid for unused arg of a unary operator.)
 *
 * The result includes all necessary quoting and schema-prefixing,
 * plus the OPERATOR() decoration needed to use a qualified operator name
 * in an expression.
 */
static char *
generate_operator_name(Oid operid, Oid arg1, Oid arg2)
{
	StringInfoData buf;
	HeapTuple	opertup;
	Form_pg_operator operform;
	char	   *oprname;
	char	   *nspname;
	Operator	p_result;

	initStringInfo(&buf);

	opertup = SearchSysCache1(OPEROID, ObjectIdGetDatum(operid));
	if (!HeapTupleIsValid(opertup))
		elog(ERROR, "cache lookup failed for operator %u", operid);
	operform = (Form_pg_operator) GETSTRUCT(opertup);
	oprname = NameStr(operform->oprname);

	/*
	 * The idea here is to schema-qualify only if the parser would fail to
	 * resolve the correct operator given the unqualified op name with the
	 * specified argtypes.
	 */
	switch (operform->oprkind)
	{
		case 'b':
			p_result = oper(NULL, list_make1(makeString(oprname)), arg1, arg2,
							true, -1);
			break;
		case 'l':
			p_result = left_oper(NULL, list_make1(makeString(oprname)), arg2,
								 true, -1);
			break;
		case 'r':
			p_result = right_oper(NULL, list_make1(makeString(oprname)), arg1,
								  true, -1);
			break;
		default:
			elog(ERROR, "unrecognized oprkind: %d", operform->oprkind);
			p_result = NULL;	/* keep compiler quiet */
			break;
	}

	if (p_result != NULL && oprid(p_result) == operid)
		nspname = NULL;
	else
	{
		nspname = get_namespace_name(operform->oprnamespace);
		appendStringInfo(&buf, "OPERATOR(%s.", quote_identifier(nspname));
	}

	appendStringInfoString(&buf, oprname);

	if (nspname)
		appendStringInfoChar(&buf, ')');

	if (p_result != NULL)
		ReleaseSysCache(p_result);

	ReleaseSysCache(opertup);

	return buf.data;
}

/*
 * generate_collation_name
 *		Compute the name to display for a collation specified by OID
 *
 * The result includes all necessary quoting and schema-prefixing.
 */
char *
generate_collation_name(Oid collid)
{
	HeapTuple	tp;
	Form_pg_collation colltup;
	char	   *collname;
	char	   *nspname;
	char	   *result;

	tp = SearchSysCache1(COLLOID, ObjectIdGetDatum(collid));
	if (!HeapTupleIsValid(tp))
		elog(ERROR, "cache lookup failed for collation %u", collid);
	colltup = (Form_pg_collation) GETSTRUCT(tp);
	collname = NameStr(colltup->collname);

	if (!CollationIsVisible(collid))
		nspname = get_namespace_name(colltup->collnamespace);
	else
		nspname = NULL;

	result = quote_qualified_identifier(nspname, collname);

	ReleaseSysCache(tp);

	return result;
}

/*
 * Given a C string, produce a TEXT datum.
 *
 * We assume that the input was palloc'd and may be freed.
 */
static text *
string_to_text(char *str)
{
	text	   *result;

	result = cstring_to_text(str);
	pfree(str);
	return result;
}

/*
 * Generate a C string representing a relation's reloptions, or NULL if none.
 */
static char *
flatten_reloptions(Oid relid)
{
	char	   *result = NULL;
	HeapTuple	tuple;
	Datum		reloptions;
	bool		isnull;

	tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
	if (!HeapTupleIsValid(tuple))
		elog(ERROR, "cache lookup failed for relation %u", relid);

	reloptions = SysCacheGetAttr(RELOID, tuple,
								 Anum_pg_class_reloptions, &isnull);
	if (!isnull)
	{
		Datum		sep,
					txt;

		/*
		 * We want to use array_to_text(reloptions, ', ') --- but
		 * DirectFunctionCall2(array_to_text) does not work, because
		 * array_to_text() relies on flinfo to be valid.  So use
		 * OidFunctionCall2.
		 */
		sep = CStringGetTextDatum(", ");
		txt = OidFunctionCall2(F_ARRAY_TO_TEXT, reloptions, sep);
		result = TextDatumGetCString(txt);
	}

	ReleaseSysCache(tuple);

	return result;
}
