The general query log is a log of every SQL query received from a client, as well as each client connect and disconnect. Since it's a record of every query received by the server, it can grow large quite quickly.
However, if you only want a record of queries that change data, it might be better to use the binary log instead. One important difference is that the binary log only logs a query when the transaction is committed by the server, but the general query log logs a query immediately when it is received by the server.
The general query log is disabled by default.
To enable the general query log, set the general_log
system variable to 1
. It can be changed dynamically with SET GLOBAL
. For example:
SET GLOBAL general_log=1;
It can also be set in a server option group in an option file prior to starting up the server. For example:
[mariadb] ... general_log
By default, the general query log is written to ${hostname}.log
in the datadir
directory. However, this can be changed.
One way to configure the general query log filename is to set the general_log_file
system variable. It can be changed dynamically with SET GLOBAL
. For example:
SET GLOBAL general_log_file='mariadb.log';
It can also be set in a server option group in an option file prior to starting up the server. For example:
[mariadb] ... general_log general_log_file=mariadb.log
If it is a relative path, then the general_log_file
is relative to the datadir
directory.
However, the general_log_file
system variable can also be an absolute path. For example:
[mariadb] ... general_log general_log_file=/var/log/mysql/mariadb.log
Another way to configure the general query log filename is to set the log-basename
option, which configures MariaDB to use a common prefix for all log files (e.g. general query log, slow query log, error log, binary logs, etc.). The general query log filename will be built by adding a .log
extension to this prefix. This option cannot be set dynamically. It can be set in a server option group in an option file prior to starting up the server. For example:
[mariadb] ... log-basename=mariadb general_log
The log-basename
cannot be an absolute path. The log file name is relative to the datadir
directory.
The general query log can either be written to a file on disk, or it can be written to the general_log
table in the mysql
database. To choose the general query log output destination, set the log_output
system variable.
The general query log is output to a file by default. However, it can be explicitly chosen by setting the log_output
system variable to FILE
. It can be changed dynamically with SET GLOBAL
. For example:
SET GLOBAL log_output='FILE';
It can also be set in a server option group in an option file prior to starting up the server. For example:
[mariadb] ... log_output=FILE general_log general_log_file=queries.log
The general query log can either be written to the general_log
table in the mysql
database by setting the log_output
system variable to TABLE
. It can be changed dynamically with SET GLOBAL
. For example:
SET GLOBAL log_output='TABLE';
It can also be set in a server option group in an option file prior to starting up the server. For example:
[mariadb] ... log_output=TABLE general_log
Some rows in this table might look like this:
SELECT * FROM mysql.general_log\G *************************** 1. row *************************** event_time: 2014-11-11 08:40:04.117177 user_host: root[root] @ localhost [] thread_id: 74 server_id: 1 command_type: Query argument: SELECT * FROM test.s *************************** 2. row *************************** event_time: 2014-11-11 08:40:10.501131 user_host: root[root] @ localhost [] thread_id: 74 server_id: 1 command_type: Query argument: SELECT * FROM mysql.general_log ...
See Writing logs into tables for more information.
A user with the SUPER
privilege can disable logging to the general query log for a connection by setting the SQL_LOG_OFF
system variable to 1
. For example:
SET SESSION SQL_LOG_OFF=1;
In MariaDB 10.3.1 and later, it is possible to disable logging to the general query log for specific types of statements by setting the log_disabled_statements
system variable. This option cannot be set dynamically. It can be set in a server option group in an option file prior to starting up the server. For example:
[mariadb] ... log_output=FILE general_log general_log_file=queries.log log_disabled_statements='slave,sp'
Unix and Linux distributions offer the logrotate
utility, which makes it very easy to rotate log files. See Rotating Logs on Unix and Linux for more information on how to use this utility to rotate the general query log.
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Licensed under the Creative Commons Attribution 3.0 Unported License and the GNU Free Documentation License.
https://mariadb.com/kb/en/general-query-log/