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From: Tom Lane <tgl@sss.pgh.pa.us>
To: "Anton A. Melnikov" <aamelnikov@inbox.ru>
cc: Justin Pryzby <pryzby@telsasoft.com>,
 Richard Guo <guofenglinux@gmail.com>,
        pgsql-hackers@lists.postgresql.org,
        "Finnerty,
    Jim" <jfinnert@amazon.com>
Subject: Re: Making Vars outer-join aware
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Comments: In-reply-to "Anton A. Melnikov" <aamelnikov@inbox.ru>
	message dated "Thu, 04 May 2023 10:22:36 +0300"
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Date: Thu, 04 May 2023 08:22:04 -0400
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"Anton A. Melnikov" <aamelnikov@inbox.ru> writes:
> The thing is that for custom scan nodes as readme says:
> "INDEX_VAR is abused to signify references to columns of a custom scan t=
uple type"
> But INDEX_VAR has a negative value, so it can not be used in varnullingr=
els bitmapset.
> And therefore this improvement seems will not work with custom scan node=
s and some
> extensions that use such nodes.

Under what circumstances would you be trying to inject INDEX_VAR
into a nullingrel set?  Only outer-join relids should ever appear there.
AFAICS the change you propose would serve only to mask bugs.

			regards, tom lane