From: Guillaume Lelarge <guillaume@lelarge.info>
To: Dave North <DNorth@signiant.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Database size Vs performance degradation
Date: Wed, 30 Jul 2008 19:51:47 +0200
Message-ID: <4890AA33.6000309@lelarge.info> (raw)
In-Reply-To: <35FABCF85D99464FB00BC5123DC2A70A05244E0C@s228130hz1ew09.apptix-01.savvis.net>
References: <35FABCF85D99464FB00BC5123DC2A70A051D0FB8@s228130hz1ew09.apptix-01.savvis.net>
<Pine.GSO.4.64.0807301220480.13698@westnet.com>
<35FABCF85D99464FB00BC5123DC2A70A05244E0C@s228130hz1ew09.apptix-01.savvis.net>
Dave North a écrit :
> [...]
>> I'd suggest re-tuning as follows:
>>
>> 1) Increase shared_buffers to 10,000, test. Things should be
>> a bit faster.
>>
>> 2) Increase checkpoint_segments to 30, test. What you want
>> to watch for here whether there are periods where the server
>> seems to freeze for a couple of seconds. That's a
>> "checkpoint spike". If this happens, reduce
>> checkpoint_segments to some sort of middle ground; some
>> people never get above 10 before it's a problem.
>>
>> 3) Increase shared_buffers in larger chunks, as long as you
>> don't see any problematic spikes you might usefully keep
>> going until it's set to at least 100,000 before improvements
>> level off.
>
> Do you happen to know if these are "reload" or "restart" tunable
> parameters? I think I've read somewhere before that they are restart
> parameters (assuming I've set SHMMAX high enough of course)
>
shared_buffers and checkpoint_segments both need a restart.
> [...]
> I have to say, I've learnt a whole load from you folks here this
> morning...very enlightening. I'm now moving on to your site Greg! :)
>
There's much to learn from Greg's site. I was kinda impressed by all the
good articles in it.
--
Guillaume.
http://www.postgresqlfr.orghttp://dalibo.com
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To: pgsql-performance@postgresql.org
Cc: guillaume@lelarge.info, DNorth@signiant.com
Subject: Re: Database size Vs performance degradation
In-Reply-To: <4890AA33.6000309@lelarge.info>
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