Horton

Re: logical decoding and replication of sequences, take 2

Dilip Kumar <dilipbalaut@gmail.com>

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From: Dilip Kumar <dilipbalaut@gmail.com>
To: Tomas Vondra <tomas.vondra@enterprisedb.com>
Cc: "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, Amit Kapila <amit.kapila16@gmail.com>, "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>, Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Masahiko Sawada <sawada.mshk@gmail.com>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Date: 2023-12-06T09:05:13Z
Lists: pgsql-hackers

Commits

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  1. Migrate logical slots to the new node during an upgrade.

  2. Make test_decoding ddl.out shorter

  3. Fix snapshot handling in logicalmsg_decode

  4. doc: Adjust a few more references to "postmaster"

  5. Revert "Logical decoding of sequences"

On Wed, Dec 6, 2023 at 11:12 AM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> On Sun, Dec 3, 2023 at 11:22 PM Tomas Vondra
> <tomas.vondra@enterprisedb.com> wrote:
> >

I was also wondering what happens if the sequence changes are
transactional but somehow the snap builder state changes to
SNAPBUILD_FULL_SNAPSHOT in between processing of the smgr_decode() and
the seq_decode() which means RelFileLocator will not be added to the
hash table and during the seq_decode() we will consider the change as
non-transactional.  I haven't fully analyzed that what is the real
problem in this case but have we considered this case? what happens if
the transaction having both ALTER SEQUENCE and nextval() gets aborted
but the nextva() has been considered as non-transactional because
smgr_decode() changes were not processed because snap builder state
was not yet SNAPBUILD_FULL_SNAPSHOT.

-- 
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com