Re: Forced to use UNION ALL when having multiple ANY operators and ORDER BY LIMIT

From: Peter Geoghegan <pg(at)bowt(dot)ie>
To: benoit <benoit(at)hopsandfork(dot)com>
Cc: "pgsql-performance(at)lists(dot)postgresql(dot)org" <pgsql-performance(at)lists(dot)postgresql(dot)org>
Subject: Re: Forced to use UNION ALL when having multiple ANY operators and ORDER BY LIMIT
Date: 2023-06-12 20:34:50
Message-ID: CAH2-Wzm7Hq69evXDC2Q3BU+HWm-s9w7qdBpXuNK8PraRweSkpA@mail.gmail.com
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On Mon, Jun 12, 2023 at 1:17 PM benoit <benoit(at)hopsandfork(dot)com> wrote:
> Is there a misusage of my indexes?
>
> Is there a limitation when using ANY or IN operators and ordered LIMIT behind?

It's complicated. Do you find that you get satisfactory performance if
you force a bitmap index scan? In other words, what is the effect of
"set enable_indexscan = off" on your original query? Does that speed
up execution at all? (I think that this approach ought to produce a
plan that uses a bitmap index scan in place of the index scan, without
changing anything else.)

--
Peter Geoghegan

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