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Re: shared_buffers advice

From: Cédric Villemain <cedric(dot)villemain(dot)debian(at)gmail(dot)com>
To: Konrad Garus <konrad(dot)garus(at)gmail(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: shared_buffers advice
Date: 2010-05-27 15:24:28
Message-ID: AANLkTik-595CJXX5_LQZQ0D7MgRXmMB41b3hnqZsZLA_@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-performance
2010/5/27 Konrad Garus <konrad(dot)garus(at)gmail(dot)com>:
> 2010/5/27 Cédric Villemain <cedric(dot)villemain(dot)debian(at)gmail(dot)com>:
>
>> pgmincore() and pgmincore_snapshot() both are able to mmap up to 1GB.
>
> Does it mean they can occupy 1 GB of RAM? How does it relate to amount
> of page buffers mapped by OS?

well, that is the projection of file in memory. only projection, but
the memory is still acquire. It is ok to rework this part and project
something like 128MB and loop. (in fact the code is needed for 9.0
because segment can be > 1GB, I didn't check what is the optimum
projection size yet)
So both yes at your questions :)

>
> --
> Konrad Garus
>



-- 
Cédric Villemain               2ndQuadrant
http://2ndQuadrant.fr/     PostgreSQL : Expertise, Formation et Support

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