From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andrew Gierth <andrew@tao11.riddles.org.uk>
Cc: pgsql-hackers@lists.postgresql.org
Cc: kes-kes@yandex.ru
Subject: Re: mark/restore failures on unsorted merge joins
Date: Tue, 24 Nov 2020 13:33:30 -0500
Message-ID: <293167.1606242810@sss.pgh.pa.us> (raw)
In-Reply-To: <87k0ua4p4u.fsf@news-spur.riddles.org.uk>
References: <87o8jn50be.fsf@news-spur.riddles.org.uk>
<125707.1606161260@sss.pgh.pa.us>
<87k0ua4p4u.fsf@news-spur.riddles.org.uk>
Andrew Gierth <andrew@tao11.riddles.org.uk> writes:
> "Tom" == Tom Lane <tgl@sss.pgh.pa.us> writes:
> Tom> Uh, why would you not just look to see if the ammarkpos/amrestrpos
> Tom> fields are non-null?
> We don't (in the back branches) seem to have a pointer to the
> IndexAmRoutine handy, only the oid?
Oh, sorry, I misread your comment to be that you wanted to add a field
to IndexAmRoutine. You're right, the real issue here is that
ExecSupportsMarkRestore lacks any convenient access to the needed info,
and we need to add a bool to IndexOptInfo to fix that.
I don't see any compelling reason why you couldn't add the field at
the end in the back branches; that's what we usually do to avoid
ABI breaks. Although actually (counts fields...) it looks like
there's at least one pad byte after amcanparallel, so you could
add a bool there without any ABI consequence, resulting in a
reasonably natural field order in all branches.
regards, tom lane
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To: pgsql-hackers@postgresql.org
Cc: tgl@sss.pgh.pa.us, andrew@tao11.riddles.org.uk, pgsql-hackers@lists.postgresql.org, kes-kes@yandex.ru
Subject: Re: mark/restore failures on unsorted merge joins
In-Reply-To: <293167.1606242810@sss.pgh.pa.us>
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