RE: query performance - getting started
- From: "Stephens, Chris" <Chris.Stephens@xxxxxxx>
- To: "Finn.Jorgensen@xxxxxxxxxxxxxxxxx" <Finn.Jorgensen@xxxxxxxxxxxxxxxxx>, "'Joel.Patterson@xxxxxxxxxxx'" <Joel.Patterson@xxxxxxxxxxx>, "'oracle-l@xxxxxxxxxxxxx'" <oracle-l@xxxxxxxxxxxxx>
- Date: Fri, 8 Apr 2011 13:50:15 -0500
The atomic_refresh parameter of dbms_mview.refresh can be used to refresh via
truncate. I'm not completely caught up on oracle-l so if this was pointed out
already, sorry.
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Jorgensen, Finn
Sent: Thursday, April 07, 2011 12:48 PM
To: 'Joel.Patterson@xxxxxxxxxxx'; 'oracle-l@xxxxxxxxxxxxx'
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@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Joel.Patterson@xxxxxxxxxxx
Sent: Thursday, April 07, 2011 8:51 AM
To: Joel.Patterson@xxxxxxxxxxx; oracle-l@xxxxxxxxxxxxx
Cc: kylelf@xxxxxxxxx
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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