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Re: Huge performance problem between 7.4.1 and 8.0.3 -

From: "Matthew T(dot) O'Connor" <matthew(at)zeut(dot)net>
To: Robert Creager <Robert_Creager(at)LogicalChaos(dot)org>
Cc: PGPerformance <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Huge performance problem between 7.4.1 and 8.0.3 -
Date: 2005-07-18 04:18:43
Message-ID: 42DB2DA3.6000909@zeut.net (view raw or flat)
Thread:
Lists: pgsql-performance
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(at)zeut(dot)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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Next:From: Robert CreagerDate: 2005-07-18 04:32:59
Subject: Re: Huge performance problem between 7.4.1 and 8.0.3 - CS
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Subject: Re: Huge performance problem between 7.4.1 and 8.0.3 - CS

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