From: Tom Lane <tgl@sss.pgh.pa.us>
To: Masahiko Sawada <sawada.mshk@gmail.com>
cc: Noah Misch <noah@leadboat.com>, Joe Conway <mail@joeconway.com>,
        Peter Eisentraut <peter@eisentraut.org>,
        Alexander Korotkov <aekorotkov@gmail.com>,
        "Guo,
    Adam" <adamguo@amazon.com>,
        "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>,
        Nathan Bossart <nathandbossart@gmail.com>,
        Jim Mlodgenski <jimmy76@gmail.com>
Subject: Re: pg_trgm comparison bug on cross-architecture replication due to different char implementation
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Comments: In-reply-to Masahiko Sawada <sawada.mshk@gmail.com>
	message dated "Tue, 10 Sep 2024 14:51:51 -0700"
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Date: Tue, 10 Sep 2024 17:56:47 -0400
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Masahiko Sawada <sawada.mshk@gmail.com> writes:
> On Tue, Sep 10, 2024 at 11:57 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Yeah, that seems like it could work.  But are we sure that replicas
>> get a copy of the primary's control file rather than creating their
>> own?

> Yes, I think so. Since at least the system identifiers of primary and
> replicas must be identical for physical replication, if replicas use
> their own control files then they cannot start the replication.

Got it.  So now I'm wondering if we need all the complexity of storing
stuff in the GIN metapages.  Could we simply read the (primary's)
signedness out of pg_control and use that?  We might need some caching
mechanism to make that cheap enough, but accessing the current index's
metapage is far from free either.

			regards, tom lane