Re: rollback segment with optimal size

When any transaction gets to the last un-extended extent it looks to see if the initial extent is available. If it is then the transaction will use the initial extent then worry about shrinking the extents after another cycle through. Oracle will keep the extended extents available until the new transactions get to the end of the initial extents, because if it was needed last time they may be needed again. Remember there is a lot of overhead involved in adding and deleting extents. If they go around again and the initial extent is available it will free up the extended extents only if there are no uncommitted transactions in any of the extended extents. Oracle will then wait for the transactions in the extended extents to be committed before freeing up the extents. Also remember that more then one transaction will use a rollback segment. The optimal size has to be your extent size times min extents. Hope this helps.

Bill

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William Dangren
Navis Enterprises
407.348.6401
800.219.0207 Received on Fri Aug 13 1999 - 08:22:54 CDT