Horton

Re: Support logical replication of DDLs

Amit Kapila <amit.kapila16@gmail.com>

View thread
From: Amit Kapila <amit.kapila16@gmail.com>
To: Zheng Li <zhengli10@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, vignesh C <vignesh21@gmail.com>, Ajin Cherian <itsajin@gmail.com>, "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>, "wangw.fnst@fujitsu.com" <wangw.fnst@fujitsu.com>, Runqi Tian <runqidev@gmail.com>, Peter Smith <smithpb2250@gmail.com>, li jie <ggysxcq@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Masahiko Sawada <sawada.mshk@gmail.com>, Japin Li <japinli@hotmail.com>, rajesh singarapu <rajesh.rs0541@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2023-03-30T10:31:47Z
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 Wed, Mar 29, 2023 at 10:23 PM Zheng Li <zhengli10@gmail.com> wrote:
>
> On Wed, Mar 29, 2023 at 5:13 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > On Wed, Mar 29, 2023 at 2:49 AM Zheng Li <zhengli10@gmail.com> wrote:
> > >
> > >
> > > I agree that a full fledged DDL deparser and DDL replication is too
> > > big of a task for one patch. I think we may consider approaching this
> > > feature in the following ways:
> > > 1. Phased development and testing as discussed in other emails.
> > > Probably support table commands first (as they are the most common
> > > DDLs), then the other commands in multiple phases.
> > > 2. Provide a subscription option to receive the DDL change, raise a
> > > notice and to skip applying the change. The users can listen to the
> > > DDL notice and implement application logic to apply the change if
> > > needed. The idea is we can start gathering user feedback by providing
> > > a somewhat useful feature (compared to doing nothing about DDLs), but
> > > also avoid heading straight into the potential footgun situation
> > > caused by automatically applying any mal-formatted DDLs.
> > >
> >
> > Doesn't this mean that we still need to support deparsing of such DDLs
> > which is what I think we don't want?
>
> I think we can send the plain DDL command string and the search_path
> if we don't insist on applying it in the first version. Maybe the
> deparser can be integrated later when we're confident that it's
> ready/subset of it is ready.
>

I think this will have overhead for users that won't need it and we
have to anyway remove it later when deparsing of such commands is
added. Personally, I don't think we need to do this to catch the apply
errors.

-- 
With Regards,
Amit Kapila.