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Subject: Re: regression in PG 15.1
From: Scott Ribe <scott_ribe@elevated-dev.com>
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Date: Mon, 28 Nov 2022 21:55:22 -0700
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Precedence: bulk

OK, this is not a regression, but a combination of things:

- in 14, it is searching all partitions, but is fast enough that I never =
noticed (log_min_duration is 1s)
- in 15, at first try it took 30s for JIT, oops
- with that turned off, performance was still really bad
- statistics were not properly updated after the upgrade to 15
  - and a big jump was made in a monotonically increasing serial being =
searched on
- instead of 142 index scans, 141 returning 0, and 1 returning a few =
rows, we got 142 seq scans
- problem fixed itself while I was still figuring it all out, because of =
normal vacuum thresholds=