Kbase 18035: Oracle err 1555 Snapshot too old rollback segment too small
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
18/06/1998 |
|
Oracle err 1555 Snapshot too old rollback segment too small
When Oracle records are being updated, Oracle stores them in a
Rollback Segment. Other processes that try to read these records
will actually be reading them from the Rollback segment.
Oracle error 1555 can occur when a long-running query attempts to
accesses records that are held in the Rollback segment and they
can no longer be found. If you receive this error, please contact
Oracle for more information. You can also refer to the Oracle
documentation for this error for a more complete description of what
can cause it. A common solution to the problem is to have
large enough Rollback segments and, more importantly, several Rollback
segments. It is often not enough to simply increase the size of a
rollback segment -- you may need to add several new rollback segments.
The following information is an excerpt from the Oracle documentation:
Insufficient Rollback Segments:A long running query may not be able to
reconstruct the snapshot of the blocks it is reading because the roll
back data is not available. This can happen when the database has many
transactions that are changing data, then committing or rolling back.
The rollback data can be overwritten if the rollback segments are too
small for the number and size of the changes being made.