Oracle-L: RE: insert performance

From: DENNIS WILLIAMS <DWILLIAMS_at_LIFETOUCH.COM>
Date: Thu, 11 Apr 2002 06:44:46 -0800
Message-ID: <F001.00441B9F.20020411064446@fatcity.com>

Paul - How many insert processes did you run on each system? Is the disk layout identical in terms of spreading across devices? Dennis Williams
DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com

-----Original Message-----
Sent: Wednesday, April 10, 2002 6:43 PM
To: Multiple recipients of list ORACLE-L

Greetings!

I am trying to diagnose a performance difference between two databases running the same test. They are similarly configured (same SGA size, etc.), and the servers are identical except for the number of CPUs (server A has 4, server B has 6).

On database A, INSERT performance is about 190 rows/second.

On database B, INSERT performance is over 500 rows/second.

I saw some cache buffers chains, buffer busy, and library cache latch waits on database A while the test was running, as well as redo log sync waits. The waits didn't seem excessive, though. I checked for "checkpoint not complete" redo allocation messages in database A's alert log and found none. The db_block_lru_latches parameter is set to one-half the number of CPUs in both machines.

I'd much appreciate any suggestions as to what else to check. I know that freelists can be an issue (there are multiple sessions performing inserts); how can I check to see if there's freelist contention? Anything else I should investigate?

Many TIA,

Paul Baumgartel, Adept Computer Associates, Inc. paul.baumgartel_at_aya.yale.edu

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Author: Paul Baumgartel
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Author: DENNIS WILLIAMS
INET: DWILLIAMS_at_LIFETOUCH.COM

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