RE: db_file_multiblock_read_count and performance

From: <ryan_gaffuri_at_comcast.net>
Date: Mon, 06 Dec 2004 19:47:10 +0000
Message-Id: <120620041947.6038.41B4B73E0003088A000017962205886360079D9A00000E09A1020E979D@comcast.net>

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lex,

we have system stats running here in production. we have about 500,000 users and about 100 GB of space. We are noticing no improvement in the percentage of queries that generate acceptable plans. if we set the index parameters more appropriate 'even with' system stats, we get an improvement. System stats by itself does not appear to help at all.
> CBO costs, though;
> The only thing you do while playing with the parameter is to make CBO
> *believe* that full table scans will be cheaper. In 9.2, enable system stats
> gathering and run your jobs --
> Then you will see the average number of blocks actually achieved by the
> multi block reads...
> Tom Kyte Seminar: http://www.naturaljoin.nl/events/seminars.html
> ----------------------------------------------------------------

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From: "Lex de Haan" <lex.de.haan_at_naturaljoin.nl> To: <ryan_gaffuri_at_comcast.net>, <Oracle-L_at_freelists.org> Subject: RE: db_file_multiblock_read_count and performance Date: Mon, 6 Dec 2004 17:49:54 +0000
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Received on Mon Dec 06 2004 - 13:52:22 CST