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.
Each line that shows when a client connects also includes
using
to indicate
the protocol used to establish the connection.
connection_type
connection_type
is one of
TCP/IP
(TCP/IP connection established without
SSL), SSL/TLS
(TCP/IP connection established
with SSL), Socket
(Unix socket file
connection), Named Pipe
(Windows named pipe
connection), or Shared Memory
(Windows shared
memory connection).
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 is in contrast with that of the binary log, for which statements are written after they are executed but before any locks are released. In addition, the query log may contain statements that only select data while such statements are never written to the binary log.
When using statement-based binary logging on a replication source server, statements received by its replicas are written to the query log of each replica. Statements are written to the query log of the source if a client reads events with the mysqlbinlog utility and passes them to the server.
However, when using row-based binary logging, updates are sent as
row changes rather than SQL statements, and thus these statements
are never written to the query log when
binlog_format
is
ROW
. A given update also might not be written
to the query log when this variable is set to
MIXED
, depending on the statement used. See
Section 19.2.1.1, “Advantages and Disadvantages of Statement-Based and Row-Based
Replication”, for more information.
By default, the general query log is disabled. To specify the
initial general query log state explicitly, use
--general_log[={0|1}]
. With no
argument or an argument of 1,
--general_log
enables the log. With
an argument of 0, this option disables the log. To specify a log
file name, use
--general_log_file=
.
To specify the log destination, use the
file_name
log_output
system variable (as
described in Section 7.4.1, “Selecting General Query Log and Slow Query Log Output Destinations”).
If you specify the TABLE
log destination, see
Log Tables and “Too many open files” Errors.
If you specify no name for the general query log file, the default
name is
. The
server creates the file in the data directory unless an absolute
path name is given to specify a different directory.
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
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). To rename the file and create a new one, use the following commands:
$> mv host_name.log host_name-old.log
$> mysqladmin flush-logs general
$> mv host_name-old.log backup-directory
On Windows, use rename rather than mv.
You can also 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.
To disable or enable general query logging for the current
session, set the session
sql_log_off
variable to
ON
or OFF
. (This assumes
that the general query log itself is enabled.)
Passwords in statements written to the general query log are
rewritten by the server not to occur literally in plain text.
Password rewriting can be suppressed for the general query log by
starting the server with the
--log-raw
option. This option may
be useful for diagnostic purposes, to see the exact text of
statements as received by the server, but for security reasons is
not recommended for production use. See also
Section 8.1.2.3, “Passwords and Logging”.
An implication of password rewriting is that statements that
cannot be parsed (due, for example, to syntax errors) are not
written to the general query log because they cannot be known to
be password free. Use cases that require logging of all statements
including those with errors should use the
--log-raw
option, bearing in mind
that this also bypasses password rewriting.
Password rewriting occurs only when plain text passwords are expected. For statements with syntax that expect a password hash value, no rewriting occurs. If a plain text password is supplied erroneously for such syntax, the password is logged as given, without rewriting.
The log_timestamps
system
variable controls the time zone of timestamps in messages written
to the general query log file (as well as to the slow query log
file and the error log). It does not affect the time zone of
general query log and slow query log messages written to log
tables, but rows retrieved from those tables can be converted from
the local system time zone to any desired time zone with
CONVERT_TZ()
or by setting the
session time_zone
system
variable.