Cached blocks and performance

From: Norman Dunbar <Norman.Dunbar_at_lfs.co.uk>
Date: Thu, 29 Aug 2002 17:02:19 +0100
Message-ID: <E2F6A70FE45242488C865C3BC1245DA702935A68@lnewton.leeds.lfs.co.uk>

Oracle caches blocks in either the DB_BUFFER_CACHE or the KEEP_POOL or the RECYCLE_POOL (depending on the version and any options you specified when creating the object of course).

So if a read requires a single row from a table, Oracle has to check if it is already in the cache and if so this counts as a logical read. If not, go to the disc and read one block Oracle block that is) into the cache (= one physical read) then read from the cache (= one logical read).

Does this help ?

Regards,
Norman.

Norman Dunbar
Database/Unix administrator
Lynx Financial Systems Ltd.
mailto:Norman.Dunbar_at_LFS.co.uk

Tel: 0113 289 6265
Fax: 0113 289 3146
URL: http://www.Lynx-FS.com


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-----Original Message-----
From: bliss_jonathan_at_hotmail.com (Jonathan Bliss) [mailto:bliss_jonathan_at_hotmail.com]
Posted At: Thursday, August 29, 2002 4:55 PM Posted To: server
Conversation: Cached blocks and performance Subject: Cached blocks and performance

Please bear with me if this is a stupid question - it is more of a learning exercise than a real question although the train of thought was prompted by a real situation.

<SNIP> Received on Thu Aug 29 2002 - 11:02:19 CDT