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A slightly more charitable view of this situation is that an optimization which was previously triggering to make the query fast suddenly no longer applied.
by mikepurvis 7y ago
A slightly more charitable view of this situation is that an optimization which was previously triggering to make the query fast suddenly no longer applied.
- SketchySeaBeast 7y agoI think that might be too optimistic - it went from a table with thousands of records to hundreds of millions of records. If I were to speak technically the oracle optimizer "did a derp".
- PeterisP 7y agoSo... stale statistics? I.e. the optimizer making the query plan assuming that the table has thousands of records (because that's what it had earlier) and now it has hundreds of millions of records? A sudden order of magnitude change in table sizes isn't normal operation, for most DB platforms that requires running some "everything's different now, please recalculate statistics" command to maintain proper functioning.