Tag Archives: performance

query cache tuning

Posted on 2009/07/08 by

For anyone, who has questions about MySQL query cache tuning, try this tuning assistant: http://dom.as/tech/query-cache-tuner/

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On file system benchmarks

Posted on 2009/06/30 by

I see this benchmark being quoted in multiple places, and there I see stuff like: When carrying out more database benchmarking, but this time with PostgreSQL, XFS and Btrfs were too slow to even complete this test, even when it … Continue reading →

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Linux 2.6.29

Posted on 2009/03/24 by

2.6.29 was released. I don’t usually write about linux kernel releases, thats what Slashdot is for :), but this one introduces write barriers in LVM, as well as ext4 with write barriers enabled by default. If you run this kernel … Continue reading →

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stupid innodb tricks

Posted on 2009/03/14 by

When it comes to extreme tuning, this is how I got +5% performance in one of my tests on 8-cpu machine (contended at mtr_commit()): gdb -p $(pidof mysqld) -ex “set srv_spin_wait_delay=50″ -batch P.S. was probably worth posting this just to … Continue reading →

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Eyecandy mutexes!

Posted on 2009/02/15 by

In my quest of making MySQL usable, I managed to hit contention that wasn’t spotted by performance masters before. Meet most useless mutex ever (this is actual contention event, not just a hold): Count nsec Lock 1451 511364 mysqld`ut_list_mutex nsec … Continue reading →

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plockstat fail!

Posted on 2009/02/06 by

Solaris has this beautiful tool ‘plockstat’ that can report application lock contention and hold events (hold events turn into contention events at parallelism.. ;-) It is just a frontend to a set of dtrace rules, that monitor mutexes and rwlocks. … Continue reading →

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ZFS and MySQL … not yet

Posted on 2008/11/15 by

Today I attended kick-ass ZFS talk (3 hours of incredibly detailed material presented by someone who knows the stuff and knows how to talk) at CEC (Sun internal training event/conference), so now I know way more about ZFS than I … Continue reading →

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On SSDs, rotations and I/O

Posted on 2008/11/09 by

Every time anyone mentions SSDs, I have a feeling of futility and being useless in near future. I have spent way too much time to work around limitations of rotational media, and understand the implications of whole vertical data stack … Continue reading →

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On XFS write barriers

Posted on 2008/11/03 by

I’m very naive, when I have to trust software. I just can’t believe a filesystem may have a tunable that makes it 20x faster (or rather, doesn’t make it 20x slower). I expect it to work out of the box. … Continue reading →

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Progress in percents: 0 1 2 3 …

Posted on 2008/10/26 by

Well, servers usually don’t crash ( our English Wikipedia master is running for 800 days, on white-box hardware, RAID0, 4.0 ;-), but when they do (like some kernel bugs on our big big boxes), one of most painful experiences is … Continue reading →

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