Mark, how do you manually remove objects from buffer cache? I saw you
writing before that you know how to do it and I would be very interested to
know also if it is not trade secret of course.
Alex Hillman
-----Original Message-----
Sent: Friday, May 04, 2001 11:11 PM
To: Multiple recipients of list ORACLE-L
Been here: this is a really interesting exercise! You can query v$bh (or
its x$ base table) which has a record for every buffer cache block. Link
on object ID's While tuning a 3000Tx/sec OLTP database I could get constant
24*7 performance by by examining objects in the buffer cache and manually
removing unwanted objects at end of business day. This prevents required
objects being aged out and having to be reloaded. Typical scenario is to
remove the index for the partition for 'todays' transactions to make room
in the buffer cache for 'tomorrows' transactions. Its good fun tuning at
this level. I wrote a gui via perl & DBI that dumped the bcache contents
(similar to the oracle tablespace manager gui) and allows objects to be
manually/automatically removed from memory. I think DB2 can do this
already. Does 9i allow definition of custom buffer pools
(buffer_pool_Transactions for example), each with its own aging algorithm?
Ive got the 9i beta cd here but havent even opened it. Too busy.
Mark Teehan
Singapore
From: "Bunyamin K.Karadeniz" <[EMAIL PROTECTED]>
Date: Wed, 2 May 2001 09:23:57 +0300
Subject: Which tables are in buffer cache.?
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Hi all gurus,
=20
I want to learn the way to ook at=20
Which tables are in buffer cache./Analyzed?
Is there a system view showing these tables??
Thanks to All.
Bunyamin K.Karadeniz
Database Group / Information Systems Department=20
HAVELSAN Ankara /TURKEY
Tel : +903122873565 / 1681
Mobile Tel : +90 535 3357729
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