Horton

Re: Support logical replication of DDLs

rajesh singarapu <rajesh.rs0541@gmail.com>

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From: rajesh singarapu <rajesh.rs0541@gmail.com>
To: Ajin Cherian <itsajin@gmail.com>
Cc: Zheng Li <zhengli10@gmail.com>, li jie <ggysxcq@gmail.com>, vignesh C <vignesh21@gmail.com>, Peter Smith <smithpb2250@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>, Amit Kapila <amit.kapila16@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, Japin Li <japinli@hotmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-11-29T04:39:33Z
Lists: pgsql-hackers

Commits

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  1. Add a run_as_owner option to subscriptions.

  2. Refactor pgoutput_change().

  3. Print the correct aliases for DML target tables in ruleutils.

  4. Fix object identity string for transforms

  5. Add grantable MAINTAIN privilege and pg_maintain role.

  6. Get rid of recursion-marker values in enum AlterTableType

  7. Release cache tuple when no longer needed

  8. Empty search_path in logical replication apply worker and walsender.

  9. Refactor format_type APIs to be more modular

  10. Use wrappers of PG_DETOAST_DATUM_PACKED() more.

Thanks Ajin for the reply.

We "Create/Install" these trigger function at the time of "Create
publication", (CreatePublication())
but If I create a replication slot using something like "select * from
pg_create_logical_replication_slot('test1', 'test_decoding')"
we would not install these triggers in the system, so we dont get DDLs
decoded, right ?

I am a bit new to this postgres, is there anything missing in my understanding ?

thanks
Raejsh

On Tue, Nov 29, 2022 at 9:55 AM Ajin Cherian <itsajin@gmail.com> wrote:
>
> On Tue, Nov 29, 2022 at 1:29 PM rajesh singarapu
> <rajesh.rs0541@gmail.com> wrote:
> >
> > One question,
> >
> > I understand that we create/enable triggers on create publication command flow.
> > I am wondering how this works in case of logical replication using slots.
> >
> >
> > thanks
> > Rajesh
> >
> Rajesh,
>
> The triggers functions when invoked write these ddl commands to WAL
> and the logical decoding WAL sender which is
> registered for that replication slot decodes the WAL logged DDL
> commands and sends them as logical replication
> messages to the subscriber side. The apply worker on the subscriber
> side, then converts these messages to actual
> DDL commands and executes them.
>
> regards,
> Ajin Cherian
> Fujitsu Australia