Comments on: Dynamic General and Slow Query Log Before MySQL 5.1

By: Four Short Links, Oct 14, 2009 | ghostar

Four Short Links, Oct 14, 2009 | ghostar — Fri, 24 Dec 2010 01:13:19 +0000

[...] Dynamic general and slow query log before MySQL 5.1 – This is an interesting way of handling the slow and general query logs on pre-5.1 MySQL instances. We don’t need this on slow, but there’s been occasions that we’ve needed the general query log, but enabling it and disabling it requires a full restart of the service on 5.0 and earlier. You still take a performance hit because you’re always logging, but I would think it to be fairly minimized on modern fast hardware. [...]

By: » Four Short Links, Oct 14, 2009 Just Another ITS Systems Guy

» Four Short Links, Oct 14, 2009 Just Another ITS Systems Guy — Wed, 14 Oct 2009 16:42:36 +0000

By: Log Buffer #165: a Carnival of the Vanities for DBAs | Pythian Group Blog

Log Buffer #165: a Carnival of the Vanities for DBAs | Pythian Group Blog — Fri, 09 Oct 2009 16:55:36 +0000

[...] Sheeri Cabral relates a little hack she found to simulate a dynamic general and slow query log before MySQL 5.1. She writes, “If you are in a similar position — where you frequently need to turn the [...]

By: Sheeri Cabral

Sheeri Cabral — Thu, 08 Oct 2009 14:45:37 +0000

Raymond — yes, so if the general query log is in

/var/lib/mysql/mysql-general.log

then an ls -l would show

/var/lib/mysql/mysql-general.log -> /dev/null

And to “turn the query log on” all they need to do is:

rm /var/lib/mysql/mysql-general.log

and at the mysql command prompt:

mysql> FLUSH LOGS;

By: Take a look at mk-query-digest | MySQL Expert | MySQL Performance | MySQL Scalability

Thu, 08 Oct 2009 13:49:46 +0000

[...] just wrote about Dynamic General and Slow Query Log Before MySQL 5.1 which apart from the File I/O overhead is an idea I’d not considered before. What may be a [...]

By: raymond

raymond — Thu, 08 Oct 2009 02:47:58 +0000

Hi…I am begineer of Mysql,

According to the hack which you mention, it General and slow query log is turn on ‘all the while’ but spool to /dev/null.

So when they needed the actual output , will it mean just change the location will do ?