07.06.11 00:45, Josh Berkus написав(ла):
All,
Just got this simple case off IRC today:
8.4.4
This plan completes in 100ms:
Filter: (NOT (hashed SubPlan 1))
9.0.2
This plan does not complete in 15 minutes or more:
Filter: (NOT (SubPlan 1))
"Hashed" is the key. Hashed subplans usually has much better performance.
You need to increase work_mem. I suppose it is in default state as you
need not too much memory for hash of 70K integer values.
BTW: Why do it want to materialize a result of seq scan without filter.
I can see no benefits (or is it more narrow rows?)
Best regards, Vitalii Tymchyshyn
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