Comments on: How to decrease InnoDB shutdown times

By: Andy Blyler

Andy Blyler — Wed, 27 Oct 2010 12:07:55 +0000

You can also execute the following SQL query to get the current count of the dirty pool pages, instead of using mysqladmin:

show global status like ‘Innodb_buffer_pool_pages_dirty’;

By: Wagner Bianchi

Wagner Bianchi — Fri, 10 Sep 2010 19:02:26 +0000

Sorry, *Take care

By: Wagner Bianchi

Wagner Bianchi — Fri, 10 Sep 2010 19:02:04 +0000

Take when issue a KILL -9 command against mysqld. If MySQL is answering any writes on any MyISAM tables, you’ll see problems that would be repaired.

By: Coway Zhou

Coway Zhou — Fri, 10 Sep 2010 17:17:50 +0000

I tried it once. But it never worked. I lost patient and did a kill -9. Of course, when the db was started, it did long time in recovery. At least it showed some progress in recovery.

By: kerja keras

kerja keras — Mon, 19 Oct 2009 03:39:12 +0000

great tips, its very helpful. thanks for share

By: Baron Schwartz

Baron Schwartz — Thu, 14 May 2009 17:36:46 +0000

Kayra, it can become negative because the insert buffer survives after restart and merging can continue after the server is started again. Peter tells me he has seen servers take weeks to catch up in some cases!

By: Kayra Otaner

Kayra Otaner — Thu, 14 May 2009 16:16:50 +0000

Even after all the updating threads shut down, you’ll see Innodb_buffer_pool_pages_dirty count approaching to 0 but still increasing sometimes. This is because of InnoDB merges, you can observe this using ‘show engine innodb status\G’. Only when all the merges are completed pages_dirty count will be 0 and stay at zero. To calculate how many merges still need to be done :
Under “INSERT BUFFER AND ADAPTIVE HASH INDEX” section difference between ‘Inserts’ and ‘merged recs’ will show how many to go. Example :

————————————-
INSERT BUFFER AND ADAPTIVE HASH INDEX
————————————-
Ibuf: size 4185, free list len 3748, seg size 7934,
65171060 inserts, 65171060 merged recs, 10552858 merges
Hash table size 7055701, used cells 32410, node heap has 33 buffer(s)

65171060 – 65171060 = 0

this means that Innodb_buffer_pool_pages_dirty should be 0 and stay at 0. Please note this calculation works most of the time, but sometimes ‘inserts’ – ‘merged recs’ value goes negative values.

By: Wagner Bianchi

Wagner Bianchi — Sat, 18 Apr 2009 01:47:26 +0000

This is a very good idea.
So nice.

By: Kevin Burton

Kevin Burton — Fri, 17 Apr 2009 16:51:30 +0000

Another note… we have three replicas of everything.

When we restart an InnoDB box it is taken out of production and does not serve requests.

Then we flush the innodb buffer pools, then restart it.

The script I linked to above is just added as a one liner to our /etc/init.d/mysql script…. if InnoDB isn’t running on this box it isn’t run.

We have about 1/2 of our cluster on MyISAM without InnoDB enabled so this would break otherwise.

By: Kevin Burton

Kevin Burton — Fri, 17 Apr 2009 16:49:03 +0000

Hey Baron….

Here’s the script we’re using:

http://pastebin.com/f5ec2f70d

If we were to write it again it would almost certainly be written in python.

Kevin