How to enable MySQL Query Log?

First, Remember that this logfile can grow very large on a busy server.

For mysql < 5.1.29:

To enable the query log, put this in /etc/my.cnf in the [mysqld] section

log   = /path/to/query.log  #works for mysql < 5.1.29

Also, to enable it from MySQL console

SET general_log = 1;

See http://dev.mysql.com/doc/refman/5.1/en/query-log.html

For mysql 5.1.29+

With mysql 5.1.29+ , the log option is deprecated. To specify the logfile and enable logging, use this in my.cnf in the [mysqld] section:

general_log_file = /path/to/query.log
general_log      = 1

Alternately, to turn on logging from MySQL console (must also specify log file location somehow, or find the default location):

SET global general_log = 1;

Also note that there are additional options to log only slow queries, or those which do not use indexes.

Take a look on this answer to another related question. It shows how to enable, disable and to see the logs on live servers without restarting.

Log all queries in mysql

Here is a summary:

If you don't want or cannot restart the MySQL server you can proceed like this on your running server:

Create your log tables (see answer)
Enable Query logging on the database (Note that the string 'table' should be put literally and not substituted by any table name. Thanks Nicholas Pickering)

SET global general_log = 1;
SET global log_output = 'table';

View the log

select * from mysql.general_log;

Disable Query logging on the database

SET global general_log = 0;

Clear query logs without disabling

TRUNCATE mysql.general_log

This was already in a comment, but deserves its own answer: Without editing the config files: in mysql, as root, do

SET global general_log_file='/tmp/mysql.log'; 
SET global log_output = 'file';
SET global general_log = on;

Don't forget to turn it off afterwards:

SET global general_log = off;

I use this method for logging when I want to quickly optimize different page loads. It's a little tip...

Logging to a TABLE

SET global general_log = 1;
SET global log_output = 'table';

You can then select from my mysql.general_log table to retrieve recent queries.

I can then do something similar to tail -f on the mysql.log, but with more refinements...

select * from mysql.general_log 
where  event_time  > (now() - INTERVAL 8 SECOND) and thread_id not in(9 , 628)
and argument <> "SELECT 1" and argument <> "" 
and argument <> "SET NAMES 'UTF8'"  and argument <> "SHOW STATUS"  
and command_type = "Query"  and argument <> "SET PROFILING=1"

This makes it easy to see my queries that I can try and cut back. I use 8 seconds interval to only fetch queries executed within the last 8 seconds.

You can disable or enable the general query log (which logs all queries) with

SET GLOBAL general_log = 1 # (or 0 to disable)

How to enable MySQL Query Log?

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