From: Tom Lane <tgl@sss.pgh.pa.us>
To: Peter Geoghegan <pg@bowt.ie>
cc: pgsql-committers <pgsql-committers@lists.postgresql.org>
Subject: Re: pgsql: Add deduplication to nbtree.
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Comments: In-reply-to Peter Geoghegan <pg@bowt.ie>
	message dated "Sun, 01 Mar 2020 13:37:16 -0800"
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Date: Sun, 01 Mar 2020 17:14:03 -0500
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Peter Geoghegan <pg@bowt.ie> writes:
> Attached patch shows how this could work. I prefer my original
> approach, but I can see the argument for doing it this way.

This does seem a bit duplicative ... and shouldn't both code paths
include a final "Assert(d == vacposting->ndeletedtids)"?  So maybe
we're better off just rejecting the Coverity complaint.

> If we keep my original approach, we should still add a new
> "ItemPointerIsValid(&itup->t_tid)" assertion that covers the plain
> tupe case in a way that mirrors the current "_bt_posting_valid(itup)"
> assert.

Another thing that maybe bears closer scrutiny is the size calculation.
It seems a bit confused as to whether the offset of the posting list
within the tuple, or the total tuple size, or both, needs to be
MAXALIGN'd.

			regards, tom lane