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List:       pgsql-performance
Subject:    Re: [PERFORM] Survey: Max TPS you've ever seen
From:       Mark Kirkwood <mark.kirkwood () catalyst ! net ! nz>
Date:       2015-02-12 23:10:46
Message-ID: 54DD32F6.6010100 () catalyst ! net ! nz
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On 13/02/15 00:20, Gudmundsson Martin (mg) wrote:
> Hi all!
> 
> > - checkpoint_segments 1000
> > - checkpoint_completion_target 0.9
> > - wal_buffers  256MB
> > - shared_buffers 31 gb
> > - max_connections 500
> 
> I see that some of you are using wal_buffers = 256MB.
> I was under the impression that Postgres will not benefit from higher value than \
> the segment size, i.e. 16MB. More than that will not do/help anything. 
> What's the reasoning behind setting it to higher than 16MB? Do I have old \
> information? 
> Best regards, Martin
> 

There was some discussion a while ago in which 32MB and 8MB both 
demonstrated better performance than 16MB (probably related to the fact 
the the default wal file size is 16MB). We just experimented further 
with bigger values, and saw some improvement.

Cheers

Mark


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