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Re: Column Filtering in Logical Replication

Alvaro Herrera <alvherre@alvh.no-ip.org>

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From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Rahila Syed <rahilasyed90@gmail.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Tomas Vondra <tomas.vondra@enterprisedb.com>, Peter Smith <smithpb2250@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2021-12-14T16:43:48Z
Lists: pgsql-hackers 
On 2021-Dec-13, Alvaro Herrera wrote:

> I think this means we need a new OBJECT_PUBLICATION_REL_COLUMN value in
> the ObjectType (paralelling OBJECT_COLUMN), and no new ObjectClass
> value.  Looking now to confirm.

After working on this a little bit more, I realized that this is a bad
idea overall.  It causes lots of complications and it's just not worth
it.  So I'm back at my original thought that we need to throw an ERROR
at ALTER TABLE .. DROP COLUMN time if the column is part of a
replication column filter, and suggest the user to remove the column
from the filter first and reattempt the DROP COLUMN.

This means that we need to support changing the column list of a table
in a publication.  I'm looking at implementing some form of ALTER
PUBLICATION for that.

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/
"Find a bug in a program, and fix it, and the program will work today.
Show the program how to find and fix a bug, and the program
will work forever" (Oliver Silfridge)

Commits

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

  1. Doc: Explain about Column List feature.

  2. Doc: fix column list vs. replica identity rules.

  3. Prohibit combining publications with different column lists.

  4. Fix the check to limit sync workers.

  5. Wait for subscription to sync in t/031_column_list.sql

  6. Move prattrs to the pg_publication_rel section in docs

  7. Allow specifying column lists for logical replication

  8. Fix row filters with multiple publications

  9. Fix publish_as_relid with multiple publications

  10. Add some additional tests for row filters in logical replication.

  11. Add index on pg_publication_rel.prpubid

  12. Avoid using DefElemAction in AlterPublicationStmt

  13. Small cleanups related to PUBLICATION framework code

  14. Add PublicationTable and PublicationRelInfo structs

  15. Fix various concurrency issues in logical replication worker launching