Horton

Re: doc: improve the restriction description of using indexes on REPLICA IDENTITY FULL table.

Masahiko Sawada <sawada.mshk@gmail.com>

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From: Masahiko Sawada <sawada.mshk@gmail.com>
To: Peter Smith <smithpb2250@gmail.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2023-07-12T07:00:25Z
Lists: pgsql-hackers

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On Tue, Jul 11, 2023 at 5:31 PM Peter Smith <smithpb2250@gmail.com> wrote:
>
> Here are my comments for v4.
>
> ======
>
> Docs/Comments:
>
> All the docs and updated comments LTGM, except I felt one sentence
> might be written differently to avoid nested parentheses.
>
> BEFORE
> ...used for REPLICA IDENTITY FULL table (see
> FindUsableIndexForReplicaIdentityFull() for details).
>
> AFTER
> ...used for REPLICA IDENTITY FULL table. See
> FindUsableIndexForReplicaIdentityFull() for details.
>
> ====

Agreed. I've attached the updated patch. I'll push it barring any objections.

>
> Logic:
>
> What was the decision about the earlier question [1] of
> removing/merging the function IsIndexOnlyOnExpression()?
>

I don't think we have concluded any action for it. I agree that
IsIndexOnlyOnExpression() is redundant. We don't need to check *all*
index fields actually. I've attached a draft patch. It removes
IsIndexOnlyOnExpression() and merges
RemoteRelContainsLeftMostColumnOnIdx() to
FindUsableIndexForReplicaIdentityFull. One concern is that we no
longer do the assertion check with
IsIndexUsableForReplicaIdentityFull(). What do you think?

Regards,

-- 
Masahiko Sawada
Amazon Web Services: https://aws.amazon.com

Commits

  1. Remove unnecessary checks for indexes for REPLICA IDENTITY FULL tables.

  2. Allow the use of a hash index on the subscriber during replication.

  3. Doc: clarify the conditions of usable indexes for REPLICA IDENTITY FULL tables.

  4. Allow the use of indexes other than PK and REPLICA IDENTITY on the subscriber.