Horton

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

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Cc: "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, Dilip Kumar <dilipbalaut@gmail.com>, "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>, Peter Smith <smithpb2250@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Bruce Momjian <bruce@momjian.us>, Julien Rouhaud <rjuju123@gmail.com>, vignesh C <vignesh21@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>
Date: 2023-09-22T06:44:38Z
Lists: pgsql-hackers 
On Fri, Sep 22, 2023 at 11:59 AM Bharath Rupireddy
<bharath.rupireddyforpostgres@gmail.com> wrote:
>
> On Thu, Sep 21, 2023 at 6:54 PM Hayato Kuroda (Fujitsu)
> <kuroda.hayato@fujitsu.com> wrote:
> >
>
> 1.
> +    /*
> +     * Use max_slot_wal_keep_size as -1 to prevent the WAL removal by the
> +     * checkpointer process.  If WALs required by logical replication slots
> +     * are removed, the slots are unusable.  This setting prevents the
> +     * invalidation of slots during the upgrade. We set this option when
>
> IIUC, during upgrade we don't want the checkpointer to remove WAL that
> may be needed by logical slots, for that the patch overrides the user
> set value for max_slot_wal_keep_size. What if the WAL is removed
> because of the wal_keep_size setting?
>

We are fine with the WAL removal unless it can invalidate the slots
which is prevented by max_slot_wal_keep_size.

>
> 3. Does this patch support upgrading of logical replication slots on a
> streaming standby?
>

No, and a note has been added by the patch for the same.

-- 
With Regards,
Amit Kapila.

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.