Re: MV logs with Oracle's auto extent control

A Truncate doesn't actually do a "drop and recreate". It drops all extents *after* the first one.
Apparently, your first extent for those MVLog Tables has been 8MB. Why ? Not sure yet.
But here's a suggestion. Try dropping and recreating the MV logs. (DROP SNAPSHOT LOG ON TABLE <tablename> ; followed by the CREATE SNAPSHOT LOG ... ) Hemant
At 09:26 PM Friday, Thomas Day wrote:
>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?
>

Hemant K Chitale
http://hemantoracledba.blogspot.com

ohandas_gandhi.html

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