SQL Error Log Plugin
Contents
The SQL_ERROR_LOG
plugin collects errors sent to clients in a log file defined by sql_error_log_filename, so that they can later be analyzed. The log file can be rotated if sql_error_log_rotate is set.
Errors are logged as they happen and an error will be logged even if it was handled by a condition handler and was never technically sent to the client.
Comments are also logged, which can make the log easier to search. But this is only possible if the client does not strip the comments away. For example, mysql command-line client only leaves comments when started with the --comments option.
Installing the Plugin
Although the plugin's shared library is distributed with MariaDB by default, the plugin is not actually installed by MariaDB by default. There are two methods that can be used to install the plugin with MariaDB.
The first method can be used to install the plugin without restarting the server. You can install the plugin dynamically by executing INSTALL SONAME or INSTALL PLUGIN. For example:
INSTALL SONAME 'sql_errlog';
The second method can be used to tell the server to load the plugin when it starts up. The plugin can be installed this way by providing the --plugin-load or the --plugin-load-add options. This can be specified as a command-line argument to mariadbd or it can be specified in a relevant server option group in an option file. For example:
[mariadb] ... plugin_load_add = sql_errlog
Uninstalling the Plugin
You can uninstall the plugin dynamically by executing UNINSTALL SONAME or UNINSTALL PLUGIN. For example:
UNINSTALL SONAME 'sql_errlog';
If you installed the plugin by providing the --plugin-load or the --plugin-load-add options in a relevant server option group in an option file, then those options should be removed to prevent the plugin from being loaded the next time the server is restarted.
Things logged
The current log format before 10.10 is:
Time User Error_code: Error_message : Query
Starting from 10.11 the format is:
Time User Type Error_code: Error_message : Query
Each separated by a space or : as above
Option | Description | Version |
---|---|---|
Time | Time (YYYY-MM-DD hh-mm-ss) | 5.5.22 |
User | privilege_user [login_user_name] @ hostname [ip] | 5.5.22 |
Type | ERROR or WARNING | 10.11.6 |
Error_code | OS error, MariaDB storage engine code (120-199) or MariaDB internal error code (1000-) | 5.5.22 |
Query | Query text | 5.5.22 |
Example of logs
2023-10-31 15:54:37 root[root] @ localhost [] ERROR 1146: Table 'test.t_doesnt_exist' doesn't exist : select * from t_doesnt_exist 2023-10-31 15:54:37 root[root] @ localhost [] ERROR 1064: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'syntax_error_query' at line 1 : syntax_error_query 2023-10-31 15:54:37 root[root] @ localhost [] ERROR 1146: Table 'test.temptab' doesn't exist : SELECT `c` FROM `temptab`
Example usage
install plugin SQL_ERROR_LOG soname 'sql_errlog'; Query OK, 0 rows affected (0.00 sec) use test; Database changed set sql_mode='STRICT_ALL_TABLES,NO_ENGINE_SUBSTITUTION'; Query OK, 0 rows affected (0.00 sec) CREATE TABLE foo2 (id int) ENGINE=WHOOPSIE; ERROR 1286 (42000): Unknown storage engine 'WHOOPSIE' \! cat data/sql_errors.log 2013-03-19 9:38:40 msandbox[msandbox] @ localhost [] ERROR 1286: Unknown storage engine 'WHOOPSIE' : CREATE TABLE foo2 (id int) ENGINE=WHOOPSIE
Versions
Version | Status | Introduced |
---|---|---|
1.0 | Stable | MariaDB 10.1.13 |
1.0 | Gamma | MariaDB 10.0.10 |
1.0 | Alpha | MariaDB 5.5.22 |
System Variables
sql_error_log
- Description: Controls how the server should treat the plugin when the server starts up.
- Valid values are:
OFF
- Disables the plugin without removing it from the mysql.plugins table.ON
- Enables the plugin. If the plugin cannot be initialized, then the server will still continue starting up, but the plugin will be disabled.FORCE
- Enables the plugin. If the plugin cannot be initialized, then the server will fail to start with an error.FORCE_PLUS_PERMANENT
- Enables the plugin. If the plugin cannot be initialized, then the server will fail to start with an error. In addition, the plugin cannot be uninstalled with UNINSTALL SONAME or UNINSTALL PLUGIN while the server is running.
- See Plugin Overview: Configuring Plugin Activation at Server Startup for more information.
- Valid values are:
- Commandline:
--sql-error-log=value
- Data Type:
enumerated
- Default Value:
ON
- Valid Values:
OFF
,ON
,FORCE
,FORCE_PLUS_PERMANENT
sql_error_log_filename
- Description: The name of the logfile. Rotation of it will be named like
sql_error_log_filename.001
- Commandline:
--sql-error-log-filename=value
- Scope: Global
- Dynamic: No
- Data Type:
string
- Default Value:
sql_errors.log
sql_error_log_rate
- Description: The rate of logging.
SET sql_error_log_rate=300;
means that one of 300 errors will be written to the log.
Ifsql_error_log_rate
is0
the logging is disabled.
The default rate is1
(every error is logged). - Commandline:
--sql-error-log-rate=#
- Scope: Global
- Dynamic: Yes
- Data Type:
numeric
- Default Value:
1
sql_error_log_rotate
- Description: This is the 'write-only' variable. Assigning TRUE to this variable forces the log rotation.
- Commandline:
--sql-error-log-rotate={0|1}
- Scope: Global
- Dynamic: Yes
- Data Type:
boolean
- Default Value:
OFF
sql_error_log_rotations
- Description: The number of rotations. When rotated, the current log file is stored and the new empty one created.
The sql_error_log_rotations logs are stored, older are removed.
The default number of rotations is9
. - Commandline:
--sql-error-log-rotations
- Scope: Global
- Dynamic: No
- Data Type:
numeric
- Default Value:
9
- Range:
1
to999
sql_error_log_size_limit
- Description: The limitation for the size of the log file. After reaching the specified limit, the log file is rotated.
1M limit set by default. - Commandline:
--sql-error-log-size-limit=#
- Scope: Global
- Dynamic: No
- Data Type:
numeric
- Default Value:
1000000
- Range:
100
to9223372036854775807
sql_error_log_warnings
- Description: If set, log warnings in addition to errors.
- Commandline:
--sql-error-log-warnings={0,1}
- Scope: Global
- Dynamic: Yes
- Data Type:
boolean
- Default Value:
OFF
- Introduced: MariaDB 10.11.6