[mythtv-users] Issues with 0.25
Scott and Nicole Harris
snharris99 at live.com
Tue Mar 6 15:02:48 UTC 2012
> Date: Tue, 6 Mar 2012 06:26:32 -0800
> From: gary.buhrmaster at gmail.com
> To: mythtv-users at mythtv.org
> Subject: Re: [mythtv-users] Issues with 0.25
> On Tue, Mar 6, 2012 at 02:54, Terjesen Jens Peder ....
> > After a bit more digging it looks like mysqld is using 90-100% of one core for long periods of time.
> That type of CPU usage seems excessive even for
> a somewhat slow backend. It is possible that your
> database is corrupt or has bad statistics causing
> high cpu usage.
Not to be contradictory...but here I go :). If the db is corrupt or has bad statistics, why wouldn't that be the case under 0.24? It's the same data with only the 0.25 schema updates applied (IOW, the "corrupt" data should exist under 0.24 and is not added by the 0.25 upgrade [or if it was, that in itself is an issue]). The part that seems to be being overlooked here, is that users experiencing these bad recordings in 0.25 can remedy the situation by rolling back to 0.24 (myself included), suggesting that the issue is in 0.25, not hardware or corrupt data. The issue only seems to affect HDHR users and only when performing more than one recording at a time (as near as I can tell by the "me too's" in this thread). > As a first step, I would recommend you look at
> the wiki at:
> and first backup the database, and then perform
> the steps regarding "Optimize the Database".
I do all the maintenance suggested in the wiki (xfs defrag, daily optimization of the db, etc) and still am seeing the issues enumerated in this thread...under 0.25 ONLY.
> Also note that if you manually configured various
> mysql tunables in the past, you may need to
> review those settings (some of the recommendations
> from various past postings are no longer optimal).
Other than max_connections being set to suitably (much higher) amount, what other specific settings should we be looking at?
Perhaps the total revamping of the MySQL thread pool that now requires such a large increase in max_connections is contributing to the high CPU usage with multiple recordings?Is using xfs for recording drives over ex4 a potential issue?
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