RE: Performance Question - High I/O per Insert

Thanks, I'll check that out!  

From: Graeme.Farmer_at_mincom.com [mailto:Graeme.Farmer_at_mincom.com] Sent: Tuesday, October 12, 2004 4:38 PM
To: Mark Strickland
Cc: oracle-l_at_freelists.org; oracle-l-bounce_at_freelists.org Subject: RE: Performance Question - High I/O per Insert  

Have you tracked the "branch node splits" and "leaf node splits" statistics from v$sesstat for the session(s) performing the inserts?

If you have STATSPACK collecting information you should see an upward trend for these stats towards the end of the week but it would be best to target the inserting sessions to be more conclusive in testing your hypothesis. A logoff trigger may be necessary if the sessions are transient.

Graeme

"Mark Strickland" <mstrickland_at_drugstore.com>

12/10/2004 02:41 AM

To

<Graeme.Farmer_at_mincom.com>

cc

<oracle-l_at_freelists.org>, <oracle-l-bounce_at_freelists.org>

Subject

RE: Performance Question - High I/O per Insert      

No, no triggers. I believe the high I/O is due to index maintenance. When I remove the indexes or run the load with direct path, the load screams. Thx!   

Mark        

From: Graeme.Farmer_at_mincom.com [mailto:Graeme.Farmer_at_mincom.com] Sent: Sunday, October 10, 2004 5:52 AM
To: Mark Strickland
Cc: oracle-l_at_freelists.org; oracle-l-bounce_at_freelists.org Subject: RE: Performance Question - High I/O per Insert   

Any triggers on the table that refer to data found in the current week's partition? This is a classic cause of high I/O per insert.

Graeme

oracle-l-bounce_at_freelists.org wrote on 29/09/2004 05:27:28 AM:

> This is a follow-up to a question I posed earlier, but I have more
info.
> A SQL*Loader conventional path load inserts rows into a table
> partitioned by week. On the first day of a new week, the load runs as
> efficiently as expected, but as the week goes on, the load goes more
and
> more slowly. There is a single local index on each partition and the
> blevel is 2. I'm scratching my head. I realize I'm not providing
much
> info, but can anyone tell me why loading into a partition might get
> slower as the partition fills? Thx!
>
>
> Mark Strickland
>
>
>
> ________________________________
>
> From: Mark Strickland
> Sent: Wednesday, September 22, 2004 12:42 PM
> To: oracle-l_at_freelists.org
> 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.
>
>
>
> Mark Strickland
>
> Drugstore.com
>
> Seattle, WA
>
>
> --
> http://www.freelists.org/webpage/oracle-l

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