RE: query performance - getting started
- From: "Chitale, Hemant Krishnarao" <Hemant.Chitale@xxxxxx>
- To: <Joel.Patterson@xxxxxxxxxxx>
- Date: Fri, 8 Apr 2011 14:05:46 +0800
You can check to see if the MV refresh really does a TRUNCATE. If you
can query and see data while the Refresh is running, then a
DELETE-INSERT is being done.
To revert to the 9i behaviour of TRUNCATE-INSERT , set ATOMIC_REFRESH
to FALSE in your DBMS_MVIEW.REFRESH call.
(See OracleSupport article Complete Refresh Read Consistency Behavior
During Refresh and Complete Refresh Performance as Influenced by the
ATOMIC_REFRESH Refresh Parameter [ID 553464.1]
)
You can also define the MV to use Parallel Query in the COMPLETE
Refresh's.
(See OracleSupport article How to Refresh a Materialized View in
Parallel [ID 577870.1] )
Hemant K Chitale
________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of
Joel.Patterson@xxxxxxxxxxx
Sent: Thursday, April 07, 2011 8:51 PM
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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