Comments on: Making MySQL more usable: InnoDB save/restore buffer pool patch

By: Eric Bergen

Eric Bergen — Mon, 25 Jan 2010 19:04:17 +0000

This patch was the basis for the patch that was integrated into xtradb.

By: Richard Soderberg

Richard Soderberg — Thu, 21 Jan 2010 11:46:46 +0000

Something similar to the functionality of your patch was integrated into the XtraDB-9 release:

http://www.mysqlperformanceblog.com/2010/01/20/xtradb-feature-save-restore-buffer-pool/

By: yejr

yejr — Wed, 08 Oct 2008 07:26:13 +0000

Jeremy
there is a new problem, when i set innodb_buffer_pool_size as 14G, and fully fill to pool by mysqldump all database, shutdown mysqld, the size of ib_buf_pool_state is about 19Mb.

mysqldump -f -q test sbtest | gzip > /data/test.sql.gz

sbtest table fill in with 100,000,000 rows by sysbench.

ls -l ib_buf_pool_state
-rw-rw—- 1 mysql mysql 19545127 Oct 8 14:34 ib_buf_pool_state

wc -l ib_buf_pool_state
917439 ib_buf_pool_state

it took more than two hour to start mysqld, a so long time to me.
some information about my server:
dell 2950, Intel(R) Xeon(R) CPU E5335 @ 2.00GHz * 7, 16Gb Ram, MD3000(dell) storage array

thanks much

By: yejr

yejr — Wed, 08 Oct 2008 06:33:28 +0000

hi,Jeremy
yes,u’r right.after i remove ib_buf_pool_state file,it is ok

By: Jeremy Cole

Jeremy Cole — Wed, 08 Oct 2008 05:09:54 +0000

yejr,

I wouldn’t be surprised if this is a bug, if you’ve reduced the size of the buffer pool and then tried to restore state from a time when the buffer pool was larger. I’ll check into what we can do to be smarter there. Likely case would be to save the size of the buffer pool in the state file so that some intelligent decisions can be made on restart.

Regards,

Jeremy

By: Kevin Burton

Kevin Burton — Wed, 08 Oct 2008 03:51:37 +0000

DO WANT!!!!!!!!

This would be a reason to upgrade

There are so many patches and forks now that I can’t brain no more.

By: yejr

yejr — Wed, 08 Oct 2008 01:55:19 +0000

hi,Jeremy
there is a problem with it, when i shutdown mysqld and change the value of innodb_buffer_pool_size, mysqld can’t start and restore the buffer pool,some of the error log like this:

081008 9:53:39InnoDB: Warning: difficult to find free blocks from
InnoDB: the buffer pool (584 search iterations)! Consider
InnoDB: increasing the buffer pool size.
InnoDB: It is also possible that in your Unix version
InnoDB: fsync is very slow, or completely frozen inside
InnoDB: the OS kernel. Then upgrading to a newer version
InnoDB: of your operating system may help. Look at the
InnoDB: number of fsyncs in diagnostic info below.
InnoDB: Pending flushes (fsync) log: 0; buffer pool: 0
InnoDB: 210393 OS file reads, 7 OS file writes, 7 OS fsyncs
InnoDB: Starting InnoDB Monitor to print further
InnoDB: diagnostics to the standard output.

thanks much

By: Jeremy Zawodny

Jeremy Zawodny — Tue, 07 Oct 2008 19:57:18 +0000

Excellent… this would be especially helpful when you need to bounce the server for a quick change.

By: Jeremy Cole

Jeremy Cole — Tue, 07 Oct 2008 16:47:27 +0000

Sheeri,

The last patch I released, information_schema patch, as linked and discussed briefly in the post, does so.

Regards,

Jeremy

By: Sheeri

Sheeri — Tue, 07 Oct 2008 14:52:00 +0000

Awesome! We already have clients using 5.1

Does this patch lead the way for a plugin that could show the *contents* of the cache? that’d be pretty cool, to be able to see how the cache changes over time…….and to see if certain queries are in the cache when you expect them to be, etc.