Comments on: Bug fix of InnoDB scalability problem

By: JIRA: Nintendo

JIRA: Nintendo — Mon, 12 Feb 2007 20:07:10 +0000

[NIN-15] CLONE -Slow front page load times and high CPU usage…

Potential temporary solution in moving to MySQL 5.0.33 which has several performance enhancing benefits for innodb with dual core cpu’s. My hope is that the improved performance with this release will mask the inefficiencies with Notes in 77x as well…

By: peter

peter — Tue, 05 Dec 2006 14:01:21 +0000

Marcus,

Yes we were highlighting this problem to MySQL and Innobase guys for a while. Innobase developed patch with similar ideas which is now included in 5.0.30 “Enterprise” version.

By: Marcus Herou

Marcus Herou — Mon, 04 Dec 2006 17:34:22 +0000

Hi. Have you guys influenced the MySQL team to implement this soon ? Or is it already in 5.0.27 ?

I mean I could of course patch it myself investing a (hopefully) small amount of time but since it is nice to be able to run standard packages I really would like it to be GA. We will have a launch soon of an application which indeed will have heavy concurrency so a concurrency fix would be helpful

Regards

//Marcus

By: Aron Rosenberg

Aron Rosenberg — Mon, 20 Nov 2006 19:23:03 +0000

For those looking for the patch itself, it can be found here:

http://mysql.bkbits.net:8080/mysql-5.0/cset@4552a85ddHCqJ_0Ar7GHnQkDE54iAg?nav=index.html|ChangeSet@-2w

Direct link to diff is here: http://mysql.bkbits.net:8080/mysql-5.0/gnupatch@4552a85ddHCqJ_0Ar7GHnQkDE54iAg

By: peter

peter — Thu, 16 Nov 2006 04:56:44 +0000

James,

The way how Innodb does locking and appropriate code is very close in all MySQL versions, so it is not the question of it taking a lot of time to port it to 4.1

Now speaking about mainainence do not you agree the more customer will be using newer MySQL versions the less effort would be need to spent on it. Even support gets more expensive with old version as support engineers usually remember well state of things for new versions.

Now regarding choices – all I’m telling if it is important for Dathan he should voice his opinion. MySQL customers should be getting service for the money. If they voice what it important for them it would be helpful to identify how many customers actually care about 4.1

Now about 4.0 and multi cores. No one is speaking about 4.0 only 4.1 which is still used rather widely. The problem we’re speaking about existed FOREVER, attaching it to multi core CPUs is nothing else but a trick to hide complete failure of MySQL/Innodb fixing this bug which should have been fixed years ago.

I’ve complained about this problem to Heikki number of times even before joining MySQL which is 5 years ago.

Number of CPUs however does matter – the effect with large CPU numbers changes from just slowdown performance to completely unacceptable. Boxes with over 4 CPUs however existed for long time… it is just only with multi-cores they came to commodity market so amount of complaints increased.

By: James Day

James Day — Thu, 16 Nov 2006 04:11:33 +0000

Peter, it’s not just maintainence effort but people being free to work on other things. There are plenty of other things for the InnoDB team to be doing, so customer demand has to drive whether it’s worth doing this, in preference to something else that could be in 5.1 instead. Unless someone throws money at the InnoDB people sufficient to justify more employees, this is a zero sum game. Significant bugs have to be fixed, but adding support in say 4.0 for issues with multi-core CPU types that weren’t around when 4.0 was released is not strictly required, even though it is nice to have.

By: Dathan Pattishall

Dathan Pattishall — Wed, 15 Nov 2006 18:30:55 +0000

Google is looking to open source the patch, but at this time no.

By: peter

peter — Wed, 15 Nov 2006 04:30:32 +0000

Nope,

It is rather unrelated to isolation level. It should be the same with READ UNCOMMITTED.

By: JoeB

JoeB — Wed, 15 Nov 2006 03:14:03 +0000

If dirty reads are being used, this should not repro, correct?

By: peter

peter — Wed, 15 Nov 2006 01:09:40 +0000

Dathan,

As MySQL Customer you may request for patch to be included in MySQL 4.1 and more customers will scream about it the higher probability is MySQL will do it. Otherwise it might not be that interesting – the faster customers move from MySQL 4.1 the better it is for MySQL as this reduces maintainence effort.

Now regarding Google patch – did they ever OpenSource it or anything ? It would be interesting to test it out at least.