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: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Adnan DURSUN Sent: Tuesday, October 03, 2006 2:49 PM To: pgsql-performance@postgresql.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 ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster ********************************************************************** This message contains confidential information intended only for the use of the addressee(s) named above and may contain information that is legally privileged. If you are not the addressee, or the person responsible for delivering it to the addressee, you are hereby notified that reading, disseminating, distributing or copying this message is strictly prohibited. If you have received this message by mistake, please immediately notify us by replying to the message and delete the original message immediately thereafter. Thank you. FADLD Tag ********************************************************************** ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
