Horton

Re: row filtering for logical replication

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

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From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Peter Smith <smithpb2250@gmail.com>, "tanghy.fnst@fujitsu.com" <tanghy.fnst@fujitsu.com>, Euler Taveira <euler@eulerto.com>, Greg Nancarrow <gregn4422@gmail.com>, vignesh C <vignesh21@gmail.com>, Ajin Cherian <itsajin@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, Rahila Syed <rahilasyed90@gmail.com>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>, Önder Kalacı <onderkalaci@gmail.com>, japin <japinli@hotmail.com>, Michael Paquier <michael@paquier.xyz>, David Steele <david@pgmasters.net>, Craig Ringer <craig@2ndquadrant.com>, Amit Langote <amitlangote09@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-01-21T14:49:48Z
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. Release cache tuple when no longer needed

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

  3. Fix one of the tests introduced in commit 52e4f0cd47.

  4. Allow specifying row filters for logical replication of tables.

  5. Move scanint8() to numutils.c

  6. Replace Test::More plans with done_testing

  7. Reduce relcache access in WAL sender streaming logical changes

  8. Small cleanups related to PUBLICATION framework code

  9. Add a view to show the stats of subscription workers.

  10. Allow publishing the tables of schema.

  11. Doc: improve documentation of CREATE/ALTER SUBSCRIPTION.

  12. Add PublicationTable and PublicationRelInfo structs

  13. Remove unused argument "txn" in maybe_send_schema().

  14. Add prepare API support for streaming transactions in logical replication.

  15. Unify PostgresNode's new() and get_new_node() methods

  16. Use l*_node() family of functions where appropriate

  17. Add support for prepared transactions to built-in logical replication.

  18. Restore the portal-level snapshot after procedure COMMIT/ROLLBACK.

  19. Rename a parse node to be more general

  20. Remove unused column atttypmod from initial tablesync query

  21. SEARCH and CYCLE clauses

On 2022-Jan-21, houzj.fnst@fujitsu.com wrote:

> Personally, I'm a little hesitant to put the check at DDL level, because
> adding check at DDLs like ATTACH PARTITION/CREATE PARTITION OF ( [1]
> explained why we need to check these DDLs) looks a bit restrictive and
> user might also complain about that. Put the check in
> CheckCmdReplicaIdentity seems more acceptable because it is consistent
> with the existing behavior which has few complaints from users AFAIK.

I think logical replication is currently so limited that there's very
few people that can put it to real use.  So I suggest we should not take
the small number of complaints about the current behavior as very
valuable, because it just means that not a lot of people are using
logical replication in the first place.  But once these new
functionalities are introduced, it will start to become actually useful
and it will be then when users will exercise and notice weird behavior.

If ATTACH PARTITION or CREATE TABLE .. PARTITION OF don't let you
specify replica identity, I suspect it's because both partitioning and
logical replication were developed in parallel, and neither gave too
much thought to the other.  So these syntax corners went unnoticed.

I suspect that a better way to attack this problem is to let ALTER TABLE
... ATTACH PARTITION and CREATE TABLE .. PARTITION OF specify a replica
identity as necessary.

My suggestion is to avoid painting us into a corner from which it will
be impossible to get out later.

-- 
Álvaro Herrera           39°49'30"S 73°17'W  —  https://www.EnterpriseDB.com/
"La espina, desde que nace, ya pincha" (Proverbio africano)