RE: Concurrent transaction per rollback segment.
- From: "Christian Antognini" <Christian.Antognini@xxxxxxxxxxxx>
- To: <sjaffarhussain@xxxxxxxxx>
- Date: Mon, 2 Jan 2006 11:22:50 +0100
Jaffar >Can anyone tell me, that one rollback segment can handle how many >concurrent transactions? I know that oracle keeps the transaction >table in the header block of segment's. Each entry (slot) of the transaction table manages a single transaction. Therefore the number of entries is the maximum number of transactions. This is a value in the 20-200 range (about 50% of the block is used for the transaction table and each slot is about 40 bytes, see V$TYPES for more info...). But, be careful, for good performance you should, usually, never have so much concurrent transactions in a single undo segment. >I have taken the system dump of this block, but, couldn't understand >where to see for concurrent transaction value in the dump file. >Can anyone have any idea how to find out the value? Active transactions have state=10 in the transaction table. If you want to know the number of active transactions at a given time you can query V$TRANSACTION (group by XIDUSN) as well. HTH Chris -- http://www.freelists.org/webpage/oracle-l