MV logs with Oracle's auto extent control
- From: "Thomas Day" <tomdaytwo@xxxxxxxxx>
- To: oracle-l <oracle-l@xxxxxxxxxxxxx>
- Date: Fri, 5 Oct 2007 09:26:47 -0400
We're using materialized view logs for data capture. There are no
materialized views being refreshed from these logs. Instead our ETL team
reads the logs (we capture all columns) and duplicates the insert, update,
or delete. After they're done they truncate the logs.
We're also letting Oracle automatically handle the next extent size.
The problem is that the extent size of the single extent remaining after the
truncate is around 8M while the single extent for a newly created table is
62K.
My question is, is Oracle not resetting the number of times extended counter
when the ML log is truncated? You'd think that a smart algorythm would
notice when the table had been truncated. On the other hand, we're using
this mechanism in a way that Oracle never intended it to be used.
I know how the auto extension sizing is supposed to work. I'm just
wondering if there's someone on the list who knows enough about the
internals of the algorythm to shed some light on why the MV Log isn't
dropping back to the smallest extent size?
Thanks
(algorythm --- does that mean that a former US Vice President is a great
jazz drummer?)
Other related posts:
