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ORA-01555 Snapshot Too Old

184 views asked in Undo Management by UNIRAC ACE (20,050 points)

1 Answer

 
Best answer

Caused by Read consistency Mechanism.

 

ORA-01555: snapshot too old: rollback segment number string with name "string" too small

Cause: Rollback records needed by a reader for consistent read are overwritten by other writers.

Action: If in Automatic Undo Management mode, increase the setting of UNDO_RETENTION. Otherwise, use larger rollback segments.

 

The ORA-01555 snapshot too old error can be addressed by several remedies:

  1.  Re-schedule long-running queries when the system has less DML load.

  2. Increasing the size of your rollback segment (undo) size.  The ORA-01555 snapshot too old also relates to your setting for automatic undo retention.

  3. Don't fetch between commits.

    The ORA-01555 snapshot too old error can be addressed by several remedies:

  4.  Re-schedule long-running queries when the system has less DML load.

  5. Increasing the size of your rollback segment (undo) size.  The ORA-01555 snapshot too old also relates to your setting for automatic undo retention.

  6. Don't fetch between commits.

 

answered by UNIRAC ACE (20,050 points)
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