mysql scaling questions
kris at FreeBSD.org
Sun Dec 30 05:35:59 PST 2007
Gergely CZUCZY wrote:
>> I appreciate that you might be constrained by local requirements, but it's really not meaningful to compare different mysql versions if
>> your goal is to study OS performance.
> It'd be a PITA to install the both versions. Maybe now, that the ports freeze is over, i can
> do something. But honestly, every mysql version was faster on linux, than eny on FreeBSD,
> even the .22 one was faster. We start work on Jan02, I will see what can I do.
Regardless, we need a stable baseline to compare to.
>> * What database engine are you using? I have only tested with innodb but maybe you are using myisam? Please provide your exact
>> sysbench command lines.
> MyISAM, of course. InnoDB is not any good with replication, and we need backup.
OK. I tested briefly and InnoDB is almost 20 times faster on my tests
with default myisam settings. myisam runs into the usual serious mysql
scaling problems at concurrency > 8 threads (contention within the mysql
application, not a FreeBSD issue).
Still waiting for your sysbench command lines :)
>> * Compare to my config file here:
>> The default mysql config has very poor performance for innodb (you need at least innodb_thread_concurrency = 0 to disable some mysql
>> brain-death). Maybe tuning is required for myisam also.
>> * Also make sure you are using identical config settings on the two systems.
> http://phoemix.harmless.hu/mysql/ verify yourself. Only the paths are
> updated, but the main parameters are just the same.
OK, I will take your word for it.
>> * With the above, please compare read-only mode also (I think Jeff already asked you about this but I didnt see a reply). That will
>> allow us to calibrate what is going on.
> The graph is mistitled as Read-write, but it's a readonly test.
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