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From: Tom Lane <[email protected]>
To: Andres Freund <[email protected]>
Cc: Peter Geoghegan <[email protected]>
Cc: Matthias van de Meent <[email protected]>
Cc: Konstantin Knizhnik <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Subject: Re: Incorrect result of bitmap heap scan.
Date: Mon, 02 Dec 2024 12:02:39 -0500
Message-ID: <[email protected]> (raw)
In-Reply-To: <fw54ktry2576xqvztx642ee6352rwc57y5hs6arcfjeowq6yon@3njdaxumsidi>
References: <[email protected]>
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	<CAH2-Wzn9ZGt8mYMrbDMSRSps3t-ro4JNFXbAvk_jwUoKi=gANQ@mail.gmail.com>
	<[email protected]>
	<fw54ktry2576xqvztx642ee6352rwc57y5hs6arcfjeowq6yon@3njdaxumsidi>

Andres Freund <[email protected]> writes:
> I think the problematic scenario involves tuples that *nobody* can see. During
> the bitmap index scan we don't know that though. Thus the tid gets inserted
> into the bitmap. Then, before we visit the heap, a concurrent vacuum removes
> the tuple from the indexes and then the heap and marks the page as
> all-visible, as the deleted row version has been removed.

Yup.  I am saying that that qualifies as too-aggressive setting of the
all-visible bit.  I'm not sure what rule we should adopt instead of
the current one, but I'd much rather slow down page freezing than
institute new page locking rules.

			regards, tom lane

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