Re: Support logical replication of DDLs

rajesh singarapu <rajesh.rs0541@gmail.com>

From: rajesh singarapu <rajesh.rs0541@gmail.com>

To: Dilip Kumar <dilipbalaut@gmail.com>

Cc: Zheng Li <zhengli10@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>

Date: 2022-03-15T06:27:28Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Add a run_as_owner option to subscriptions.
- 482675987bcd 16.0 cited
Refactor pgoutput_change().
- da324d6cd45b 16.0 cited
Print the correct aliases for DML target tables in ruleutils.
- df931e9ab35b 11.20 landed
- c8a5f1685fb7 15.3 landed
- 4efb4f0d4878 13.11 landed
- 3dd287c14fac 12.15 landed
- 393430f57544 16.0 landed
- 14345f3c6a7b 14.8 landed
Fix object identity string for transforms
- 9a312562314a 16.0 landed
Add grantable MAINTAIN privilege and pg_maintain role.
- 60684dd834a2 16.0 cited
Get rid of recursion-marker values in enum AlterTableType
- 840ff5f451cd 16.0 cited
Release cache tuple when no longer needed
- ed0fbc8e5ac9 15.0 cited
Empty search_path in logical replication apply worker and walsender.
- 11da97024abb 14.0 cited
Refactor format_type APIs to be more modular
- a26116c6cbf4 11.0 cited
Use wrappers of PG_DETOAST_DATUM_PACKED() more.
- 3a0d473192b2 10.0 cited

+

On Sun, Mar 13, 2022 at 5:05 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> On Mon, Feb 21, 2022 at 9:43 PM Zheng Li <zhengli10@gmail.com> wrote:
> >
> > Hello,
> >
> > One of the most frequently requested improvements from our customers
> > is to reduce downtime associated with software updates (both major and
> > minor versions). To do this, we have reviewed potential contributions to
> > improving logical replication.
> >
> > I’m working on a patch to support logical replication of data
> > definition language statements (DDLs). This is a useful feature when a
> > database in logical replication has lots of tables, functions and
> > other objects that change over time, such as in online cross major
> > version upgrade.
>
> +1
+1


> > I put together a prototype that replicates DDLs using the generic
> > messages for logical decoding. The idea is to log the candidate DDL
> > string in ProcessUtilitySlow() using LogLogicalMessge() with a new
> > flag in WAL record type xl_logical_message indicating it’s a DDL
> > message. The xl_logical_message record is decoded and sent to the
> > subscriber via pgoutput. The logical replication worker process is
> > dispatched for this new DDL message type and executes the command
> > accordingly.
>
> If you don't mind, would you like to share the POC or the branch for this work?
I would love to try this patch out, would you like to share branch or POC ?