Horton

Re: pg_trgm comparison bug on cross-architecture replication due to different char implementation

Masahiko Sawada <sawada.mshk@gmail.com>

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From: Masahiko Sawada <sawada.mshk@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: "Guo, Adam" <adamguo@amazon.com>, "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>
Date: 2024-04-30T07:38:12Z
Lists: pgsql-hackers 
On Tue, Apr 30, 2024 at 12:37 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> Masahiko Sawada <sawada.mshk@gmail.com> writes:
> > On Tue, Apr 23, 2024 at 11:57 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> >> Reject as not a bug.  Discourage people from thinking that physical
> >> replication will work across architectures.
>
> > While cross-arch physical replication is not supported, I think having
> > architecture dependent differences is not good and It's legitimate to
> > fix it. FYI the 'char' data type comparison is done as though char is
> > unsigned. I've attached a small patch to fix it. What do you think?
>
> I think this will break existing indexes that are working fine.
> Yeah, it would have been better to avoid the difference, but
> it's too late now.

True. So it will be a PG18 item.

Regards,

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

Commits

  1. pg_upgrade: Check for the expected error message in TAP tests.

  2. Fix a typo in 005_char_signedness.pl test.

  3. Add test 005_char_signedness.pl to meson.build.

  4. Fix an issue with index scan using pg_trgm due to char signedness on different architectures.

  5. pg_upgrade: Add --set-char-signedness to set the default char signedness of new cluster.

  6. pg_upgrade: Preserve default char signedness value from old cluster.

  7. pg_resetwal: Add --char-signedness option to change the default char signedness.

  8. Add default_char_signedness field to ControlFileData.

  9. Remove unneeded nbtree array preprocessing assert.