Comments on: Enabling/Disabling query log without server restart in MySQL 5.0

By: vesko

vesko — Wed, 29 Sep 2010 12:13:29 +0000

Here it is. The target file is in the same dir as the link in /var/log/

lrwxrwxrwx 1 mysql mysql 14 Aug 26 05:31 mysql-full1.log -> mysql-full.log
-rwxrwxrwx 1 mysql mysql 152694272 Aug 26 05:04 mysql-full.log

MySQL is instructed to use it:

log=/var/log/mysql-full1.log

And here’s the error

07:07:19 mysqld started
^G/usr/libexec/mysqld: File ‘/var/log/mysql-full1.log’ not found (Errcode: 13)
7:07:19 [ERROR] Could not use /var/log/mysql-full1.log for logging (error 13). Turning logging off for the whole duration of the MySQL server process. To turn it on again: fix the cause, shutdown the MySQL server and restart it.

By: peter

peter — Sat, 04 Sep 2010 00:04:42 +0000

Hi,

Check out permission for directories as well. It could be there is no access to the directory where this file is located or some higher level directory.

By: vesko

vesko — Wed, 01 Sep 2010 00:49:10 +0000

I’m trying to use a symbolic link for general log file as described in your book. It seems like a nice and clean solution for enabling/disabling query log dynamically on MySQL 5.0

However I’m having the following error:

Error 13. Turning logging off for the whole duration of the MySQL server process. To turn it on again: fix the cause, shutdown the MySQL server and restart it

I made sure the symlink and the file that it points to are owned by the mysql user. It still gives me that error 13 (permission denied)

By: peter

peter — Wed, 30 Jul 2008 16:13:54 +0000

You can’t turn on/off slow query log globally in MySQL 5.0 (though you can use trick described)

By: jk

jk — Tue, 29 Jul 2008 18:15:14 +0000

allow me to follow up on this post:
So does mysql 5.0.X not allow dynamically switching general query at all?

By: peter

peter — Sat, 12 Jul 2008 00:56:17 +0000

Bill,

It was my impression this allows to disable logging statements for this session only, while I’m speaking about global log.

By: bill

bill — Sat, 12 Jul 2008 00:14:08 +0000

set sql_log_off = ‘ON’;
turns of the log without restarting

set sql_log_off = ‘OFF’;
turns it back on

this works on 5.0, anyway

By: Eike Herzbach

Eike Herzbach — Sun, 16 Sep 2007 13:50:59 +0000

Just tried out the query sniffer, it works great and is dead simple to use:

apt-get install libpcap0.8 (if needed)
curl http://iank.org/querysniffer/querysniffer-0.10.tar.gz | tar xvzf -
querysniffer-0.10/mysqlsniff.x64

I like this unobtrusive way of debugging!

Cheers,
Eike

By: peter

peter — Fri, 14 Sep 2007 10:52:08 +0000

Thanks Keith,

Indeed query sniffer is another good way to approach the same problem.

By: Keith Murphy

Keith Murphy — Thu, 13 Sep 2007 21:02:03 +0000

It seems that great minds think alike. I wasn’t aware of your patch. And the proxy hadn’t been released when we started working on our query sniffer program. The sniffer is a bit different in that is a perl program that uses the libpcap library. It can be started and stopped at any time and you can direct output to a file without any problems.