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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 18:22:10
Message-ID: AANLkTikyiXIW0BuAqN5H8ylqUm73_Ev13IPIXfsa8aeO@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>:
>
>> 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 :)
>
> So when I map 12 GB, this process will consume 1 GB and the time
> needed to browse through the whole 12 GB buffer?

Exactly. And the time to browse depend on the number of blocks already
in core memory.
I am interested by tests results and benchmarks if you are going to do some :)


>
> --
> Konrad Garus
>



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

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