The general query log is a general record of what mysqld is doing. The server writes information to this log when clients connect or disconnect, and it logs each SQL statement received from clients. The general query log can be very useful when you suspect an error in a client and want to know exactly what the client sent to mysqld.
mysqld writes statements to the query log in the order that it receives them, which might differ from the order in which they are executed. This logging order contrasts to the binary log, for which statements are written after they are executed but before any locks are released. (Also, the query log contains all statements, whereas the binary log does not contain statements that only select data.)
Control the general query log at server startup as follows:
Before 5.1.6, the general query log destination is always a
file. To enable the log, start mysqld with
the
--log[=
or file_name]-l [
option.
file_name]
As of MySQL 5.1.6, the destination can be a file or a table,
or both. Start mysqld with the
--log[=
or file_name]-l [
option to enable the general query log, and optionally use
file_name]--log-output to specify the log
destination (as described in
Section 5.2.1, “Selecting General Query and Slow Query Log Output Destinations”).
As of MySQL 5.1.12, as an alternative to
--log or -l,
use --general_log[={0|1}] to
specify the initial general query log state. In this case, the
default general query log file name is used. With no argument
or an argument of 1,
--general_log enables the log.
With an argument of 0, this option disables the log.
As of MySQL 5.1.29, use
--general_log[={0|1}] to enable
or disable the general query log, and optionally
--general_log_file=
to specify a log file name. The
file_name--log and -l
options are deprecated.
If the general query log file is enabled but no name is specified,
the default name is
host_name.log
To disable or enable the general query log or change the log file
name at runtime, use the global
general_log and
general_log_file system
variables. Set general_log to 0
(or OFF) to disable the log or to 1 (or
ON) to enable it. Set
general_log_file to specify the
name of the log file. If a log file already is open, it is closed
and the new file is opened.
When the general query log is enabled, the server writes output to
any destinations specified by the
--log-output option or
log_output system variable. If
you enable the log, the server opens the log file and writes
startup messages to it. However, further logging of queries to the
file does not occur unless the FILE log
destination is selected. If the destination is
NONE, the server writes no queries even if the
general log is enabled. Setting the log file name has no effect on
logging if the log destination value does not contain
FILE.
Server restarts and log flushing do not cause a new general query log file to be generated (although flushing closes and reopens it). On Unix, you can rename the file and create a new one by using the following commands:
shell>mvshell>host_name.loghost_name-old.logmysqladmin flush-logsshell>mvhost_name-old.logbackup-directory
On Windows, you cannot rename the general query log file while the server has it open before MySQL 5.1.3. You must stop the server, rename the file, and then restart the server to create a new log file.
As of MySQL 5.1.12, you can rename the general query log file at runtime by disabling the log:
SET GLOBAL general_log = 'OFF';
With the log disabled, rename the log file externally; for example, from the command line. Then enable the log again:
SET GLOBAL general_log = 'ON';
This method works on any platform and does not require a server restart.
The session sql_log_off variable
can be set to ON or OFF to
disable or enable general query logging for the current
connection.
The general query log should be protected because logged statements might contain passwords. See Section 6.1.2.3, “Passwords and Logging”.