Re: PostgreSQL Caching

Like many descent RDBMS, Postgresql server allocates its own shared
memory area where data is cached in. When receiving a query request,
Postgres engine checks first its shared memory buffers, if not found,
the engine performs disk I/Os to retrieve data from PostgreSQL data
files and place it in the shared buffer area before serving it back to
the client. Blocks in the shared buffers are shared by other sessions
and can therefore be possibly accessed by other sessions. Postgresql
shared buffers can be allocated by setting the postgresql.conf parameter
namely, shared_buffers.

Sincerely,

--
Husam

-----Original Message-----
From: pgsql-performance-owner(at)postgresql(dot)org
[mailto:pgsql-performance-owner(at)postgresql(dot)org] On Behalf Of Adnan
DURSUN
Sent: Tuesday, October 03, 2006 2:49 PM
To: pgsql-performance(at)postgresql(dot)org
Subject: [PERFORM] PostgreSQL Caching

Hi,

I wonder how PostgreSQL caches the SQL query results. For example ;

* does postgres cache query result in memory that done by
session A
?
* does session B use these results ?

Best Regards

Adnan DURSUN

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Thank you.

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