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From: Amit Kapila <amit.kapila16@gmail.com>
Date: Tue, 4 Jul 2023 15:21:35 +0530
Message-ID: <CAA4eK1LZ_A-UmC_P+_hLi+Pbwyqak+vRKemZ7imzk2puVTpHOA@mail.gmail.com>
Subject: Re: doc: improve the restriction description of using indexes on
 REPLICA IDENTITY FULL table.
To: Masahiko Sawada <sawada.mshk@gmail.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
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On Mon, Jul 3, 2023 at 7:45=E2=80=AFAM Masahiko Sawada <sawada.mshk@gmail.c=
om> wrote:
>
> Commit 89e46da5e5 allowed us to use indexes for searching on REPLICA
> IDENTITY FULL tables. The documentation explains:
>
> When replica identity <quote>full</quote> is specified,
> indexes can be used on the subscriber side for searching the rows.  Candi=
date
> indexes must be btree, non-partial, and have at least one column referenc=
e
> (i.e. cannot consist of only expressions).
>
> To be exact, IIUC the column reference must be on the leftmost column
> of indexes. Does it make sense to mention that?
>

Yeah, I think it is good to mention that. Accordingly, the comments
atop build_replindex_scan_key(),
FindUsableIndexForReplicaIdentityFull(), IsIndexOnlyOnExpression()
should also be adjusted.

--=20
With Regards,
Amit Kapila.