The question of how to delete 25 million rows from a table of one billion came up on the ODC database forum recently. With changes in the numbers of rows involved it’s a question that keeps coming back and I wrote a short series for AllthingsOracle a couple of years ago that discusses the issue. This note is just a catalogue of links to the articles:
- Part 1: Strategic and Tactical thinking
- Part 2: Analysing the impact on the data patterns
- Part 3: Undo, redo, concurrency and time costs
- Part 4: Threats that appear in real systems
There is an error in part 2 in the closing paragraphs – it says that the number of index entries deleted varies “from just one to 266″, it actually varies from 181 to 266.
Other reference(s)
- Massive Deletes and new features
- Purging data and rebuilding indexes
- Will a massive delete improve performance
Oracle Scratchpad 
Comments and related questions are welcome.