HELP! Problems exporting a user

Hi,

I am facing the following problem, can somebody help me with this

H/W : NCR 3550 running SVR4
Oracle version 7.0.12

The following error is returned while exporting an user from the database

    ORA 01555: "snapshot too old (rollback segment too small)"

When the rollback segments were monitored :

• There were no active transactions, though the number of writes to the rollback segment was high.
• The optimal size specified for the rollback segment was not reached.

The problem repeated even when the database was opened in restricted mode.

When logged as SYS, rollback segments were still being used, but the size of information written to the rollback segments was within the segemnt's size and so the export terminated successfully.

Currently the purpose is achieved by using a bigger rollback segment.

  Can somebody explain

1. Why write occurs in rollback segments during Export ?
2. Why "Snapshot too old error" is coming even before the optimal size of rollback segment is reached ?
3. Is there anyway to trace which transaction/session is writing to the rollback segment ?
4. Is there anyway to findout the information written on to the rollback segment ?

Thanks in advance,
--vinay Received on Thu Sep 15 1994 - 07:00:56 CEST