Horton

Re: Support logical replication of DDLs

Zheng Li <zhengli10@gmail.com>

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From: Zheng Li <zhengli10@gmail.com>
To: Dilip Kumar <dilipbalaut@gmail.com>, Ajin Cherian <itsajin@gmail.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, rajesh.rs0541@gmail.com
Date: 2022-04-11T16:42:01Z
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 →

  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.

Hi,

> > Good catch. The reason for having isTopLevel in the condition is
> > because I haven't decided if a DDL statement inside a PL should
> > be replicated from the user point of view. For example, if I execute a
> > plpgsql function or a stored procedure which creates a table under the hood,
> > does it always make sense to replicate the DDL without running the same
> > function or stored procedure on the subscriber? It probably depends on
> > the specific
> > use case. Maybe we can consider making this behavior configurable by the user.
>
> But then this could be true for DML as well right?  Like after
> replicating the function to the subscriber if we are sending the DML
> done by function then what's the problem in DDL.  I mean if there is
> no design issue in implementing this then I don't think there is much
> point in blocking the same or even providing configuration for this.

Agreed. I'll unblock DDLs in functions/procedures and test it out. I
find out some DDLs in functions are replicated multiple times on the
subscriber while they should only be replicated once. Still trying to
figure out why.

>The patch no longer applies. The patch is a very good attempt, and I
>would also like to contribute if required.
>I have a few comments but will hold it till a rebased version is available.

Hi, Ajin. That'll be great! I'll rebase my github branch to master
head. In the meantime, this github branch still works
https://github.com/zli236/postgres/tree/ddl_replication

Regards,
Zheng