Comment 6 for bug 338012

Hi Mark,

On 06/03/2009, at 7:18 AM, MARK CALLAGHAN wrote:
>> INDEX_STATISTICS allows us to find unused indexes, and that's very
>> valuable.
>> Don't care for the SHOW commands as such, in INFORMATION_SCHEMA
>> they're much more useful as they can be joined onto other tables to
>> do
>> the unused-index detection.
>>
>> Don't think OurDelta will be removing that, it's specifically why
>> we included it.
>
> Then you have inherited a mutex contention performance bug. I fixed it
> by removing the feature. There are other ways to fix it that require
> more code changes. But it needs to be fixed.

Well in the Percona/OurDelta version, there's a server param to turn
it all on/off.
So that removes the performance/contention issue most of the time, but
allows us to get the stats when wanted.
Of course it'd be even nicer to improve the code itself also, as we
won't want too much contention when it's turned on for a bit.

Cheers,
Arjen.
--
Arjen Lentz, Director @ Open Query (http://openquery.com)
Affordable Training and Pro-Active Support for MySQL & related
technologies

My blog is at http://arjen-lentz.livejournal.com
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