Re: Problems with system locking

[Ingo Strüwing]

Brian O'Donnell wrote:
...
> If system locks are indicated in SHOW
> PROCESSLIST when the system is flushing its key
> cache, and there are multiple threads trying to
> write to the same table (as is the case in our
> setup) then are they explained as contentions
> between the various INSERT statements?

Yes. This is my opinion.

> ie: one
> INSERT ends and starts flushing the key cache but
> while that happens, the next INSERT is trying to
> execute but can't because the key cache is being
> flushed???

Exactly.

> However if this is the case, I still
> don't see why the locks should cause a significant
> degradation in performance, which appears to be
> the case.

I agree. This looks odd.

> Anyway, here are the output traces from
> myisamchk...

I agree that the maximum table size is big enough for you. There should be no size problems for you. Also I don't see other possible problems with it.

Did I mention the option to use MERGE tables to you? Regularily adding a new table "at the end" and dropping the front table?

Regards

Ingo Strüwing, Senior Software Developer - Storage Engines
MySQL AB, www.mysql.com