How to enable MySQL Query Log?

Question

How do I enable the MySQL function that logs each SQL query statement received from clients and the time that query statement has submitted? Can I do that in phpmyadmin or N

Answer 1

I had to drop and recreate the general log at one point. During the recreation, character sets got messed up and I ended up having this error in the logs:

[ERROR] Incorrect definition of table mysql.general_log: expected the type of column 'user_host' at position 1 to have character set 'utf8' but found character set 'latin1'

So if the standard answer of "check to make sure logging is on" doesn't work for you, check to make sure your fields have the right character set.

Answer 2

There is bug in MySQL 5.6 version. Even mysqld show as :

    Default options are read from the following files in the given order:
C:\Windows\my.ini C:\Windows\my.cnf C:\my.ini C:\my.cnf c:\Program Files (x86)\MySQL\MySQL Server 5.6\my.ini c:\Program Files (x86)\MySQL\MySQL Server 5.6\my.cnf 

Realy settings are reading in following order :

    Default options are read from the following files in the given order:
C:\ProgramData\MySQL\MySQL Server 5.6\my.ini C:\Windows\my.ini C:\Windows\my.cnf C:\my.ini C:\my.cnf c:\Program Files (x86)\MySQL\MySQL Server 5.6\my.ini c:\Program Files (x86)\MySQL\MySQL Server 5.6\my.cnf

Check file: "C:\ProgramData\MySQL\MySQL Server 5.6\my.ini"

Hope it help somebody.

Answer 3

On Windows you can simply go to

C:\wamp\bin\mysql\mysql5.1.53\my.ini

Insert this line in my.ini

general_log_file = c:/wamp/logs/mysql_query_log.log

The my.ini file finally looks like this

...
...
...    
socket      = /tmp/mysql.sock
skip-locking
key_buffer = 16M
max_allowed_packet = 1M
table_cache = 64
sort_buffer_size = 512K
net_buffer_length = 8K
read_buffer_size = 256K
read_rnd_buffer_size = 512K
myisam_sort_buffer_size = 8M
basedir=c:/wamp/bin/mysql/mysql5.1.53
log = c:/wamp/logs/mysql_query_log.log        #dump query logs in this file
log-error=c:/wamp/logs/mysql.log
datadir=c:/wamp/bin/mysql/mysql5.1.53/data
...
...
...
...

Answer 4

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;

Answer 5

Not exactly an answer to the question because the question already has great answers. This is a side info. Enabling general_log really put a dent on MySQL performance. I left general_log =1 accidentally on a production server and spent hours finding out why performance was not comparable to a similar setup on other servers. Then I found this which explains the impact of enabling general log. http://www.fromdual.com/general_query_log_vs_mysql_performance.

Gist of the story, don't put general_log=1 in the .cnf file. Instead use set global general_log =1 for a brief duration just to log enough to find out what you are trying to find out and then turn it off.

Answer 6

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.