From: Mischa Sandberg <mischa@ca.sophos.com>
To: Jim C. Nasby <jnasby@pervasive.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Solaris shared_buffers anomaly?
Date: Tue, 13 Jun 2006 16:20:34 -0700
Message-ID: <448F4842.4010305@ca.sophos.com> (raw)
In-Reply-To: <20060613224759.GM34196@pervasive.com>
References: <1150151282.14661.42.camel@tigger>
<20060613000441.GI8588@kenobi.snowman.net>
<20060613200810.GZ34196@pervasive.com>
<448F3A6E.6080908@ca.sophos.com>
<20060613224759.GM34196@pervasive.com>
Jim C. Nasby wrote:
> On Tue, Jun 13, 2006 at 03:21:34PM -0700, Mischa Sandberg wrote:
>> Raised shared_buffers to 16000 (128MB).
>> DB server dropped to a CRAWL.
>>
>> vmstat showed that it was swapping like crazy.
>> Dropped shared_buffers back down again.
>> Swapping stopped.
>
> What's sort_mem set to? I suspect you simply ran the machine out of
> memory.
8192 (8MB). No issue when shared_buffers was 2000; same apps always.
> Also, Solaris by default will only use a portion of memory for
> filesystem caching, which will kill PostgreSQL performance.
Yep, tested /etc/system segmap_percent at 20,40,60.
No significant difference between 20 and 60.
Default is 10%? 12%? Can't recall.
Was not changed from 20 during the shared_buffer test.
--
Engineers think that equations approximate reality.
Physicists think that reality approximates the equations.
Mathematicians never make the connection.
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To: pgsql-performance@postgresql.org
Cc: mischa@ca.sophos.com, jnasby@pervasive.com
Subject: Re: Solaris shared_buffers anomaly?
In-Reply-To: <448F4842.4010305@ca.sophos.com>
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