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 Originally Posted by crysu
1. No
2. Between 70 and 90%
This is a text book case where you may want to consider deleting data by doing inserts instead of doing deletes.
Here is the scenario...
You want to delete 70%+ of the rows sitting on table_a
1- Rename table_a as table_b
2- Create table_a as select * from table_b where v_column_name > sysdate - v_retention_days
3- Build indexes
4- Gather fresh stats.
5- After business approval drop table_b
This is faster, generates less redo and ensures tables and indexes are not fragmented at the end of the process.
Can you afford a maintenance window to do it?
Pablo (Paul) Berzukov
Author of Understanding Database Administration available at amazon and other bookstores.
Disclaimer: Advice is provided to the best of my knowledge but no implicit or explicit warranties are provided. Since the advisor explicitly encourages testing any and all suggestions on a test non-production environment advisor should not held liable or responsible for any actions taken based on the given advice.
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