Horton

Re: Support logical replication of DDLs

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Zheng Li <zhengli10@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, rajesh.rs0541@gmail.com
Date: 2022-04-08T11:13:08Z
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.

On Thu, Mar 17, 2022 at 3:36 AM Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
>
> Did you see some old code I wrote towards this goal?
> https://www.postgresql.org/message-id/20150215044814.GL3391@alvh.no-ip.org
> The intention was that DDL would produce some JSON blob that accurately
> describes the DDL that was run;
>

I have read that thread and found one of your emails [1] where you
seem to be saying that JSON representation is not required for BDR.
Will in some way going via JSON blob way make this project
easier/better?

> the caller can acquire that and use it
> to produce working DDL that doesn't depend on runtime conditions.
>

For runtime conditions, one of the things you have mentioned in that
thread is to add schema name in the statement at the required places
which this patch deals with in a different way by explicitly sending
it along with the DDL statement. The other cases where we might need
deparsing are Alter Table type cases (where we need to rewrite the
table) where we may want to send a different DDL. I haven't analyzed
but I think it is better to have a list where all we need deparsing
and what is the best way to deal with it. The simpler cases seem to be
working with the approach proposed by this patch but I am not sure if
it will work for all kinds of cases.

[1] - https://www.postgresql.org/message-id/20150504185721.GB2523%40alvh.no-ip.org

-- 
With Regards,
Amit Kapila.