# &adminguide;

## Overview

Flatstore is one of so-called &osips; database modules. It does not export any functions executable from the configuration scripts, but it exports a subset of functions from the database API and thus other module can use it instead of, for example, mysql module.

The module does not export all functions of the database API, it supports only one function, insert. The module is limited but very fast. It is especially suitable for storing accounting information on sites with extremely high traffic. If MySQL is too slow or if you get a huge amount of accounting data then you can consider using this module. Note that the acc module is the only module that was tested with flastore.

The format of the files produced by this module is plain text. Each line consists of several fields, fields are separated by default by the | character. New information is always appended at the end of the file, searching, deleting and updating of existing data is not supported by the module.

The acc module can be configured to use flatstore module as database backend using the db_url_parameter:

    modparam("acc", "db_url", "flatstore:/var/log/acc")

This configuration options tells acc module that it should use the flatstore module and the flatstore module should create all files in /var/log/acc directory. The directory must exist and &osips; processes must have permissions to create files in that directory.

Name of files in that directory will follow the following pattern:

    <prefix><table_name>[_<process_name>]<suffix>

For example, without setting any module parameter, the entries writen by &osips; process 8 into acc table would be written in file acc_8.log. For each table there will be several files, one file for every &osips; process that wrote some data into that table. The main reason why there are several files for each table is that it is much faster to have one file per process, because it does not require any locking and thus &osips; processes will not block each other. To get the complete data for a table you can simply concatenate the contents of files with the same table name but different process id. Alternatively, you can use the single_file parameter, and all processes will dump the data into the same file. Note that this will induce some latency.

### Rotating Log Files

There is a new &osips; MI (management interface) command called flat_rotate. When &osips; receives the command then it will close and reopen all files used by flatstore module. The rotation itself has to be done by another application (such as logrotate). Follow these steps to rotate files generated by flatstore module:

- Rename the files that you want to rotate:

      cd /var/log/acc
      mv acc_1.log acc_1.log.20050605
      mv acc_2.log acc_2.log.20050605
      mv acc_4.log acc_3.log.20050605
      ...

  Note that at this point &osips; will still be writing all data into the renamed files.

- Send &osips; the MI command to close and reopen the renamed files. For example, using FIFO:

      opensipsctl fifo flat_rotate

  This will force &osips; to close the renamed files and open new ones with original names, such as `acc_1.log`. New files will be open at the point when &osips; has some data to write. It is normal that the files will be not created immediately if there is no traffic on the proxy server.

  Note that the suffix and prefix parameters are re-evaluated each time the flat_rotate command is issued. Therefore, after a rotate command, it is possible to open a different file than previous one.

- Move the renamed files somewhere else and process them.

## Dependencies

### &osips; Modules

The following modules must be loaded before this module:

- No dependencies on other &osips; modules.

### External Libraries or Applications

The following libraries or applications must be installed before running &osips; with this module loaded:

- None.

## Exported Parameters

### `flush` (integer)

Enable or disable flushing after each write.

Default value is 1.

#### Set flush parameter

    ...
    modparam("db_flatstore", "flush", 0)
    ...

### `delimiter` (char)

Delimiter used to separate the values.

Default value is '|'.

#### Set delimiter parameter

    ...
    modparam("db_flatstore", "delimiter", ";")
    ...

### `suffix` (string)

The suffix appended to the table name. Can be a pseudo variable.

Default value is ".log".

#### Set suffix parameter

    ...
    modparam("db_flatstore", "suffix", "$time(%H)")
    ...

### `prefix` (string)

The table name prefix. Can be a pseudo variable.

Defaul value is none.

#### Set prefix parameter

    ...
    modparam("db_flatstore", "prefix", "$time(%H)")
    ...

### `single_file` (integer)

Specifies if all the processes should dump the data into a single file.

Default value is 0.

#### Set single_file parameter

    ...
    modparam("db_flatstore", "single_file", 1)
    ...

## Exported Functions

There are no function exported to routing script.

## Exported MI Functions

### `flat_rotate`

It changes the name of the files where it is written.

Name: flat_rotate

Parameters: none

MI FIFO Command Format:

    		:flat_rotate:_reply_fifo_file_
    		_empty_line_