Help Center/ Cloud Data Migration/ FAQs/ Troubleshooting/ Why Is Error ORA-01555 Reported During Migration from Oracle to DWS?

Updated on 2023-06-21 GMT+08:00

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Why Is Error ORA-01555 Reported During Migration from Oracle to DWS?

Error ORA-01555 is reported during data migration from Oracle to DWS.

Each table contains an average of 200 to 500 million data records. Source data is updated every 10 minutes.
CDM does not support real-time migration but supports scheduled migration. As the source data is updated every 10 minutes, the source database has been updated before the migration job is complete, resulting in a rollback timeout.
If the entire table is queried during data migration and the query takes a long time, other users frequently perform the commit operation during the query, and the RBS of the Oracle database is small.

There are three solutions:

Reduce the data volume queried each time.
Increase the RBS of the Oracle data.
Reduce frequent commit operations. This requires adjustment of the production service logic, which is almost impossible.

Parent topic: Troubleshooting

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