Re: BUG #17618: unnecessary filter column <> text even after adding index - Mailing list pgsql-bugs

From Tom Lane
Subject Re: BUG #17618: unnecessary filter column <> text even after adding index
Date
Msg-id 946195.1663718159@sss.pgh.pa.us
Whole thread Raw
In response to Re: BUG #17618: unnecessary filter column <> text even after adding index  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: BUG #17618: unnecessary filter column <> text even after adding index
Re: BUG #17618: unnecessary filter column <> text even after adding index
List pgsql-bugs
I wrote:
> I wonder if that isn't backwards, ie we should prefer to put duplicates
> in bitmapqualorig (the recheck condition) instead of qpqual (the filter).
> If my head is screwed on correctly today, that should allow us to skip
> checking the condition much of the time, and the skip would be safe
> if the index is correctly asserting that no recheck is needed.

Flipping the removal around has the effect I expected on the plan shape,
but some of the regression test queries now give the wrong answer, so
there's something faulty about that analysis.

            regards, tom lane



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