Re: Yet another abort-early plan disaster on 9.3

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>> The existing cost estimation
>> code effectively assumes that they're perfectly uniformly distributed;
>> which is a good average-case assumption but can be horribly wrong in
>> the worst case.


Sorry, just an outsider jumping in with a quick comment.

Every year or two the core count goes up. Can/should/does postgres ever attempt two strategies in parallel, in cases where strategy A is generally good but strategy B prevents bad worst case behaviour? Kind of like a Schrödinger's Cat approach to scheduling. What problems would it raise?

Graeme. 



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