# &adminguide;

## Overview

This is a module which provides MySQL connectivity for OpenSIPS. It implements the DB API defined in OpenSIPS.

## 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:

- libmysqlclient-dev - the development libraries of mysql-client.

## Exported Parameters

### `exec_query_threshold` (integer)

If queries take longer than 'exec_query_threshold' microseconds, warning messages will be written to logging facility.

Default value is 0 - disabled.

#### Set `exec_query_threshold` parameter

    ...
    modparam("db_mysql", "exec_query_threshold", 60000)
    ...

### `timeout_interval` (integer)

Time interval after which a connection attempt (read or write request) is aborted. The value counts three times, as several retries are done from the driver before it gives up.

The read timeout parameter is ignored on driver versions prior to 5.1.12, 5.0.25 and 4.1.22. The write timeout parameter is ignored on version prior to 5.1.12 and 5.0.25, the 4.1 release don't support it at all.

Default value is 2 (6 sec).

#### Set `timeout_interval` parameter

    ...
    modparam("db_mysql", "timeout_interval", 2)
    ...

### `max_db_queries` (integer)

The maximum number of database queries to be executed. If this parameter is set improperly, it is set to default value.

Default value is 2.

#### Set `max_db_queries` parameter

    ...
    modparam("db_mysql", "max_db_queries", 2)
    ...

### `max_db_retries` (integer)

The maximum number of database connection retries. If this parameter is set improperly, it is set to default value.

Default value is 3.

#### Set `max_db_retries` parameter

    ...
    modparam("db_mysql", "max_db_retries", 2)
    ...

## Exported Functions

No function exported to be used from configuration file.

## Installation

Because it dependes on an external library, the mysql module is not compiled and installed by default. You can use one of the next options.

- - edit the "Makefile" and remove "db_mysql" from "excluded_modules" list. Then follow the standard procedure to install &osips;: "make all; make install".

- - from command line use: 'make all include_modules="db_mysql"; make install include_modules="db_mysql"'.

## Exported Events

### `E_MYSQL_CONNECTION`

This event is raised when a MySQL connection is lost or recovered.

Parameters:

- url - the URL of the connection as specified by the db_url parameter.

- status - connected if the connection recovered, or disconnected if the connection was lost.