Re: [gentoo-user] mysqld invoked oom-killer

[kashani]

On 7/21/2011 5:14 PM, Grant wrote:
>>>>         Any reason you're still using MyISAM tables? Innodb is almost as
>>>> fast
>>>> or much much faster than MyISAM in nearly every way these days.
>>>
>>> Can multiple processes be utilized for mysql like they are for
>>> apache2?  Perhaps not since it's a database?
>>
>>         Mysql is multithreaded and spawns a thread for each connection. Try a
>> ps -efL and you should see a number of Mysql threads. However that is part
>> of the problem with MyISAM. It throws a giant table lock blocking all other
>> threads until the SQL statement is complete. Innodb uses row locks which
>> allows the other threads to use the table.
>>
>>         As far as moving to Innodb tables it's actually easy, but with a
>> number of caveats. I'd lower your Apache max clients, tweak my.cnf, and runs
>> some load tests before getting deep into Mysql. When you're ready I'd go
>> about this way.
>
> apache MaxClients has been lowered to 50 which is a shame because I
> have 30+ separate images on each of my pages and that number can not
> be reduced.  This means I may not be able to serve more than 1 full
> page at a time.

	This is wrong.

>> 1. Make backups first.
>> 2. See if you have any full text fields. Tables with full text fields will
>> have to remain MyISAM.
>
> Many of my tables have one or more fields defined as TEXT out of
> laziness.  Should I instead come up with an appropriate char(N)
> declaration for each?  Can N go as high as necessary?

TEXT fields don't matter, FULL TEXT indexes do. Sorry my mistake.

> OK, just leave key_buffer at the default 16M?

	No. Make key_buffer 256M and then restart Mysql or update it from the 
commandline. You're starving Mysql for resources. Fix this first. Then 
you can mess around with tables and engines.

kashani