RE: Performance Question - High I/O per Insert

Wow, thanks for the quick response! Logical I/Os divided by executions. Rows_processed in v$sqlarea is currently 0.

Mark

-----Original Message-----

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Jonathan Lewis Sent: Wednesday, September 22, 2004 12:46 PM To: oracle-l_at_freelists.org
Subject: Re: Performance Question - High I/O per Insert

Conventional path still uses array inserts. How are you checking the costs -=20

    logical I/Os divided by executes
or

    logical I/Os divided by rows_processed ?

If the former, then you are probably out by a factor of the arraysize. =20

Regards

Jonathan Lewis

http://www.jlcomp.demon.co.uk/faq/ind_faq.html The Co-operative Oracle Users' FAQ

http://www.jlcomp.demon.co.uk/seminar.html Optimising Oracle Seminar - schedule updated Sept 19th

• Original Message -----=20 From: "Mark Strickland" <mstrickland_at_drugstore.com> To: <oracle-l_at_freelists.org> Sent: Wednesday, September 22, 2004 8:42 PM Subject: Performance Question - High I/O per Insert

I'm trying to understand why I'm seeing a high number of I/Os for inserts. Inserts are through SQL*Loader conventional patch. Average row length is 129 bytes, no longs or blobs. The table has five indexes and each index has a blevel of 2. According to v$sqlarea, each insert uses 650 logical I/Os, 69 physical I/Os. I would expect fewer than 20 I/Os per insert. There are db file sequential read waits on the data files that make up the index tablespace. That file system also contains the archived logs. Not surprised at the contention. Can someone point me in the right direction to understand this? Thx. =20

Mark Strickland

Drugstore.com

Seattle, WA

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http://www.freelists.org/webpage/oracle-l Received on Wed Sep 22 2004 - 14:45:41 CDT