Tag Archives: hack

Opening tables v2!

Posted on 2010/02/26 by

PMP on demand revealed one of reasons why we’ve been seeing ‘Opening tables’ during proper operations, not just during startup (see my previous post on this topic). We had a thousand or so threads waiting on LOCK_open, and the only … Continue reading →

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stupid dtrace trick

Posted on 2009/03/15 by

So, if there is no way to flush status variables of a server, one could use dtrace (and run SHOW GLOBAL STATUS ;-) #!/usr/sbin/dtrace -Fws int *zero; BEGIN { zero=alloca(4); *zero=0; } pid$target:mysqld:add_to_status*:1b { copyout(zero,uregs[R_ECX],4); copyout(zero,uregs[R_EDX],4); } P.S. This is … 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 →

Posted in mysql | Tagged , , , | 4 Comments

SHOW INNODB LOCKS

Posted on 2008/05/16 by

If implementing ‘SHOW INNODB LOCKS’ took half an hour (literally, includes compiling and testing) for a non-developer type of guy (cause most of code was written anyway), why the heck it takes ten years (or more?) to get such feature … Continue reading →

Posted in mysql | Tagged , | 5 Comments