Horton

RE: [PoC] pg_upgrade: allow to upgrade publisher node

Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>

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From: "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>
To: 'Amit Kapila' <amit.kapila16@gmail.com>
Cc: John Naylor <johncnaylorls@gmail.com>, vignesh C <vignesh21@gmail.com>, "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>, Peter Smith <smithpb2250@gmail.com>, Andres Freund <andres@anarazel.de>, Dilip Kumar <dilipbalaut@gmail.com>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Bruce Momjian <bruce@momjian.us>, Julien Rouhaud <rjuju123@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>
Date: 2023-11-30T04:12:50Z
Lists: pgsql-hackers 
Dear Amit,

> Sorry, my analysis was not complete. On looking closely, I think the
> reason is that we are allowed to upgrade the slot iff there is no
> pending WAL to be processed. 

Yes, the guard will strongly protect from data loss, but I do not take care in the test.

> The test first disables the subscription
> to avoid unnecessary LOGs on the subscriber and then stops the
> publisher node.

Right. Unnecessary ERROR would be appeared if we do not disable.

> It is quite possible that just before the shutdown of
> the server, autovacuum generates some WAL record that needs to be
> processed, 

Yeah, pg_upgrade does not ensure that autovacuum is not running *before* the
upgrade.

> so you propose just disabling the autovacuum for this test.

Absolutely correct.

Best Regards,
Hayato Kuroda
FUJITSU LIMITED

Commits

  1. Fix issues in binary_upgrade_logical_slot_has_caught_up().

  2. Fix a random failure in 003_logical_slots.pl.

  3. Fix a test in 003_logical_slots.

  4. Fix uninitialized slot array access during the upgrade.

  5. Fix the test 003_logical_slots.

  6. Commit b195e6d482 forgot to update meson.build.

  7. Use shorter file names in the upgrade logical slots test.

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

  9. Flush logical slots to disk during a shutdown checkpoint if required.

  10. Prevent possibility of panics during shutdown checkpoint.