RE: Tune for 'db file sequential read'

From: Khedr, Waleed <Waleed.Khedr_at_FMR.COM>
Date: Wed, 3 May 2000 19:10:46 -0400
Message-Id: <10486.104878@fatcity.com>

I think the problem is doing thousands of index scans (unique or range scan).
Doing thousands of random single block I/O is very sensitive to the performance of the disk system, the memory cache on the top of the disk system, the structure of the index and the size of buffer cache.

Increasing the buffer cache could help but will be very limited. Check the performance of the disks that have indexes, percentage busy, queue length, etc.
Separate heavily used indexes on separate disks.

Also your process could be using index scan on the slow system while it is using FTS on the fast one.

Regards,

Waleed

-----Original Message-----
From: Deepak Sharma [mailto:sharmakdeep_at_yahoo.com] Sent: Wednesday, May 03, 2000 2:07 PM
To: Multiple recipients of list ORACLE-L Subject: Tune for 'db file sequential read'

On querying the v$session_event, I could see one process taking a very large wait time. The process takes about 4 Hrs to complete on *this* instance (A), whereas it takes a few minutes on another instance(B) with almost same amount of data. The Metalink pages suggest to test by increasing DB_BLOCK_BUFFERS, but the interesting thing is that instance A's SGA is 128M, whereas instance B's is 44M. Any suggestions ?

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-- 
Author: Deepak Sharma
  INET: sharmakdeep_at_yahoo.com

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Received on Wed May 03 2000 - 18:10:46 CDT