Re: shared_buffers advice - Mailing list pgsql-performance

From Cédric Villemain
Subject Re: shared_buffers advice
Date
Msg-id AANLkTikyiXIW0BuAqN5H8ylqUm73_Ev13IPIXfsa8aeO@mail.gmail.com
Whole thread Raw
In response to Re: shared_buffers advice  (Konrad Garus <konrad.garus@gmail.com>)
Responses Re: shared_buffers advice  (Konrad Garus <konrad.garus@gmail.com>)
List pgsql-performance
2010/5/27 Konrad Garus <konrad.garus@gmail.com>:
> 2010/5/27 Cédric Villemain <cedric.villemain.debian@gmail.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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