Horton

Re: Support logical replication of DDLs

Dilip Kumar <dilipbalaut@gmail.com>

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From: Dilip Kumar <dilipbalaut@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Euler Taveira <euler@eulerto.com>, japin <japinli@hotmail.com>, Zheng Li <zhengli10@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, rajesh.rs0541@gmail.com, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-04-13T09:07:54Z
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.

On Tue, Apr 12, 2022 at 4:25 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> > The *initial* DDL replication is a different problem than DDL replication. The
> > former requires a snapshot to read the current catalog data and build a CREATE
> > command as part of the subscription process. The subsequent DDLs in that object
> > will be handled by a different approach that is being discussed here.
> >
>
> I think they are not completely independent because of the current way
> to do initial sync followed by replication. The initial sync and
> replication need some mechanism to ensure that one of those doesn't
> overwrite the work done by the other. Now, the initial idea and patch
> can be developed separately but I think both the patches have some
> dependency.

I agree with the point that their design can not be completely
independent.  They have some logical relationship of what schema will
be copied by the initial sync and where is the exact boundary from
which we will start sending as replication.  And suppose first we only
plan to implement the replication part then how the user will know
what all schema user has to create and what will be replicated using
DDL replication?  Suppose the user takes a dump and copies all the
schema and then creates the subscription, then how we are we going to
handle the DDL concurrent to the subscription command?

-- 
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com