From: Matthew T. O'Connor <matthew@zeut.net>
To: Robert Creager <Robert_Creager@LogicalChaos.org>
Cc: PGPerformance <pgsql-performance@postgresql.org>
Subject: Re: Huge performance problem between 7.4.1 and 8.0.3 -
Date: Mon, 18 Jul 2005 00:18:43 -0400
Message-ID: <42DB2DA3.6000909@zeut.net> (raw)
In-Reply-To: <20050717221050.7c4ac241@thunder.logicalchaos.org>
References: <20050717213416.59dcb52e@thunder.logicalchaos.org>
<42DB2684.9020706@zeut.net>
<20050717221050.7c4ac241@thunder.logicalchaos.org>
Ok, it doesn't look like an autovacuum problem. The only other thing I
can think of is that some query is doing a seq scan rather than an index
scan. Have you turned on the query logging to see what queries are
taking so long?
Matt
Robert Creager wrote:
>I am, and it is. It's ANALYZING and VACUUM'ing tables every interval (5 minutes
>- 8.0.3). Right now, for that last 4 hours, I'm not VACUUMing the 7.4.1
>database and it's still clicking along at < .2 second queries. Last year
>(7.4.1), I noticed that it took about a week of heavy activity (for this DB)
>before I'd really need a vacuum. That's when I put in the 5 min cron.
>
>When I first switched over to 8.0.3, I was still running the cron vacuum. I got
>into big trouble when I had vacuum's backed up for 6 hours. That's when I
>started noticing the query problem, and the CS numbers being high. 7.4.1
>vacuums every 5 minutes always take < 30 seconds (when I'm watching).
>
>Cheers,
>Rob
>
>When grilled further on (Sun, 17 Jul 2005 23:48:20 -0400),
>"Matthew T. O'Connor" <matthew@zeut.net> confessed:
>
>
>
>>Robert Creager wrote:
>>
>>
>>
>>>For 8.03, pg_autovacuum is running. On 7.4.1, I set up a cron job to vacuum
>>>analyze every 5 minutes.
>>>
>>>
>>>
>>>
>>Are you sure that pg_autovacuum is doing it's job? Meaning are you sure
>>it's vacuuming as often as needed? Try to run it with -d2 or so and
>>make sure that it is actually doing the vacuuming needed.
>>
>>
>
>
>
>
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Subject: Re: Huge performance problem between 7.4.1 and 8.0.3 -
In-Reply-To: <42DB2DA3.6000909@zeut.net>
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