Horton

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

Masahiko Sawada <sawada.mshk@gmail.com>

View thread View on postgr.es
From: Masahiko Sawada <sawada.mshk@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
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>
Date: 2024-09-10T21:51:51Z
Lists: pgsql-hackers 
On Tue, Sep 10, 2024 at 11:57 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> Masahiko Sawada <sawada.mshk@gmail.com> writes:
> > An alternative way would be that we store the char signedness in the
> > control file, and gin_trgm_ops opclass reads it if the bytes in the
> > meta page shows 'unset'. The char signedness in the control file
> > doesn't mean to be used for the compatibility check for physical
> > replication but used as a hint. But it also could be a bit messy,
> > though.
>
> 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.

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.