RE: query performance - getting started

From: <Joel.Patterson_at_crowley.com>
Date: Fri, 8 Apr 2011 08:22:41 -0400
Message-ID: <C95D75DD2E01DD4D81124D104D317ACA16155AD3C1_at_JAXMSG01.crowley.com>



I now have one for, one says its about the same (Complete refresh verses CTAS). We would not be dropping the table so it would be a bulk insert.

Right now I only have 4000 rows. I suspect it could climb as high as 40000, but I suspect no larger. Still going to follow the 11g path as well and the results cache suggestion and see what happens.

Joel Patterson
Database Administrator
904 727-2546



From: John Harper [mailto:harperjm_at_ldschurch.org] Sent: Thursday, April 07, 2011 4:02 PM
To: Finn.Jorgensen_at_constellation.com; Patterson, Joel; 'oracle-l_at_freelists.org' Subject: RE: query performance - getting started

There IS NO FASTER way than CTAS. If you want to really push a DB do several CTAS at the same time... I was able to accomplish 2.9 million rows/second with direct attached storage and 1.8 million rows/second over SAN (EMC Clarion).

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Jorgensen, Finn Sent: Thursday, April 07, 2011 11:48 AM
To: 'Joel.Patterson_at_crowley.com'; 'oracle-l_at_freelists.org' Subject: RE: query performance - getting started

Last time I looked into MV refreshes (in 10gR2) they did not do truncates. They do a delete of all rows. I assume this is so running queries aren't interrupted by the refresh.

So, if you have the luxury of doing a truncate and then insert (append) or better yet, drop table and CTAS, and the table is large, then that would be faster.

Thanks,
Finn

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Joel.Patterson_at_crowley.com Sent: Thursday, April 07, 2011 8:51 AM
To: Joel.Patterson_at_crowley.com; oracle-l_at_freelists.org Cc: kylelf_at_gmail.com
Subject: RE: query performance - getting started

Query performance continued.

We have a very complicated Materialized view, and a view that utilizes the MV. We cannot use Fast refresh - a complete refresh is necessary. The app can decide when the view is refreshed, and can execute dbms_refresh when necessary.

Essentially all records are truncated, and the view is rebuilt as part of the complete refresh. So, is this just as easy, efficient as any other method such as Temp tables, Truncating a permanent table and re-inserting, or other?

Moving forward,

JP

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Received on Fri Apr 08 2011 - 07:22:41 CDT

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