Horton

Re: Fix slot synchronization with two_phase decoding enabled

Nisha Moond <nisha.moond412@gmail.com>

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From: Nisha Moond <nisha.moond412@gmail.com>
To: shveta malik <shveta.malik@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>
Date: 2025-05-07T11:06:41Z
Lists: pgsql-hackers

Attachments

On Wed, May 7, 2025 at 10:32 AM shveta malik <shveta.malik@gmail.com> wrote:
>
> On Mon, May 5, 2025 at 3:29 PM Nisha Moond <nisha.moond412@gmail.com> wrote:
> >
> > Please find the v12 patch with above suggested changes.
> >
>
> Thanks for the patch. Few comments for doc changes:
>
> 1)
> func.sgml - pg_create_logical_replication_slot:
>
> +        failover. The parameters <parameter>twophase</parameter> and
> +        <parameter>failover</parameter> cannot be enabled together when
> +        creating a replication slot. However, a slot created with
> <parameter>twophase</parameter>
> +        enabled can later have <parameter>failover</parameter> set to true
> +        either using <command>ALTER_REPLICATION_SLOT</command> or via
> +        <command>ALTER SUBSCRIPTION</command> if a subscription is using this
> +        slot.
>
> Will it be better if we make a NOTE for this? Also can we create links for
> <command>ALTER SUBSCRIPTION</command> and
> <command>ALTER_REPLICATION_SLOT</command>?
>
> 2)
> protocol.sgml:
>
> +          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 the changes up to the point where two-phase decoding
> +          was enabled.
>
> Can we make a new paragraph for the new restriction added. Same for
> other new restriction in this page.
>
> 3)
> create_subscription.sgml:
>
> +          cannot be enabled together when creating a subscription. However, a
> +          <literal>two_phase</literal> enabled subscription can later have
> +          <literal>failover</literal> set to true via <command>ALTER
> SUBSCRIPTION</command>,
>
> via-->using
>

Attached is the v13 patch with the above comments addressed.

--
Thanks,
Nisha

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.