Horton

Re: Fix slot synchronization with two_phase decoding enabled

shveta malik <shveta.malik@gmail.com>

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From: shveta malik <shveta.malik@gmail.com>
To: Nisha Moond <nisha.moond412@gmail.com>
Cc: Masahiko Sawada <sawada.mshk@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, shveta malik <shveta.malik@gmail.com>
Date: 2025-05-02T09:35:15Z
Lists: pgsql-hackers 
On Fri, May 2, 2025 at 12:57 PM Nisha Moond <nisha.moond412@gmail.com> wrote:
>
>
> Please find the v11 patch addressing the above points and all other
> comments. I have also optimized the test by reducing the number of
> subscriptions and slots.
>

Thanks for the patch. Few comments:

1)

pg_upgrade/t/003_logical_slots.pl:

- "SELECT slot_name, two_phase, failover FROM pg_replication_slots");
-is($result, qq(regress_sub|t|t), 'check the slot exists on new cluster');
+ "SELECT slot_name, two_phase FROM pg_replication_slots");
+is($result, qq(regress_sub|t), 'check the slot exists on new cluster');

With this change, the failover property test during upgrade is
removed. Shall we add it again either using ALTER SUB to enable
failover and two_phase together or a new subscription with failover
alone?

2)
+          The default is false. This option cannot be set together with
+          <literal>failover</literal> when creating a logical replication slot.
+          However, once the slot is created with <literal>two_phase =
true</literal>,
+          <literal>failover</literal> can be set to true after the slot has
+          consumed all transactions up to the point where two-phase decoding
+          was enabled.


Suggestion:  all transactions --> all the changes.

thanks
Shveta

Commits

  1. Don't retreat slot's confirmed_flush LSN.

  2. Fix assertion failure during decoding from synced slots.

  3. Fix xmin advancement during fast_forward decoding.

  4. Fix slot synchronization for two_phase enabled slots.

  5. Again match pg_user_mappings to information_schema.user_mapping_options.