Comments on: The performance effects of new patches

By: Vadim

Vadim — Fri, 26 Sep 2008 01:50:42 +0000

Oliver,

This is custom scripts to prepare graphs, also we have custom scripts to emulate TPC-C load, where session is active connection to MySQL

By: Olivier

Olivier — Thu, 25 Sep 2008 15:19:07 +0000

Hi,

How did you do these graphs ?
- What is a session for you ? A connection to the host ? Doing what?
- What tools did you use to bench IO/CPU/tpm ? Sysbench ?

By: Vadim

Vadim — Fri, 12 Sep 2008 22:38:16 +0000

Xabier,

Do you use highperf release ?

Can you provide dump of table so we could test it also ?

By: Vadim

Vadim — Fri, 12 Sep 2008 22:30:11 +0000

Koa,

Yes, if you are customer.

By: Koa McCullough

Koa McCullough — Fri, 12 Sep 2008 22:22:13 +0000

Is Percona offering support packages for these new builds?

By: Xabier Eizmendi

Xabier Eizmendi — Fri, 12 Sep 2008 09:25:32 +0000

We are experiencing some problems while testing this patches. The truncation of tables is very slow (5mins to truncate 32million rows table). It used to be seconds with the official version.
We are using MySQL 5.0.67

Has anyone else had the same problem?

By: Hakan Küçükyılmaz

Hakan Küçükyılmaz — Wed, 10 Sep 2008 17:29:59 +0000

Vadim,

I see those periodic drops in TPM when running DBT2, too. I will try your setting,
maybe it will help.

Thanks for explaining the variable.

Best,

Hakan

By: Vadim

Vadim — Wed, 10 Sep 2008 17:26:40 +0000

Hakan,

We did not do any special investigation around innodb_max_dirty_pages_pct to show you results, we think in this case
InnoDB will be less aggressive in flushing dirty buffer pool pages on disk. With default configuration we see there are periodical significant drops of TPM when InnoDB starts flushing process.

By: Vadim

Vadim — Wed, 10 Sep 2008 17:22:59 +0000

Alexey,

1) We consider it is less stable comparing to standard MySQL, as it is less tested. We are going to recommend this release to customers who experience scaling problem, especially on fast IO system.

2) These are fixes to InnoDB and as Oracle owns it – it is hard to say about any plans – Oracle’s policy is not disclosure any development plans. From bug report I see InnoDB has plans to research these patches.

3) Sorry, do not fully understand what you are asking. We show results when patches show good improvement. For sure there are cases when you will not see the improvements – for example clear CPU bound cases, when data fits into buffer pool – but there should not be also performance degradation with our patches.

4) Disadvantage I see it is less tested at this moment. We are testing it on our production system, on TPC-C, TPC-E, TPC-H emulation workloads, on intensive sysbench benchmarks and we have no any problem so far. And this is help we expect from community – to help us with testing our releases.

By: Hakan Küçükyılmaz

Hakan Küçükyılmaz — Wed, 10 Sep 2008 13:38:31 +0000

Vadim,

congratulations on this huge performance gain. I have one
detail question. Why do you set
innodb_max_dirty_pages_pct = 70

I see that the default is 90. Did you do some measurements around it?