Horton

Re: row filtering for logical replication

Amit Kapila <amit.kapila16@gmail.com>

View thread
From: Amit Kapila <amit.kapila16@gmail.com>
To: Peter Smith <smithpb2250@gmail.com>
Cc: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>, Ajin Cherian <itsajin@gmail.com>, Greg Nancarrow <gregn4422@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, Euler Taveira <euler@eulerto.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: 2021-11-23T09:02:07Z
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 Thu, Nov 18, 2021 at 11:02 AM Peter Smith <smithpb2250@gmail.com> wrote:
>
> On Mon, Nov 15, 2021 at 9:31 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> >
> > 4. I think we should add some comments in pgoutput_row_filter() as to
> > why we are caching the row_filter here instead of
> > get_rel_sync_entry()? That has been discussed multiple times so it is
> > better to capture that in comments.
>
> Added comment in v40 [1]
>

I think apart from truncate and error cases, it can also happen for
other operations because we decide whether to publish a change
(operation) after calling get_rel_sync_entry() in pgoutput_change. I
think we can reflect that as well in the comment.

> >
> > 5. Why do you need a separate variable rowfilter_valid to indicate
> > whether a valid row filter exists? Why exprstate is not sufficient?
> > Can you update comments to indicate why we need this variable
> > separately?
>
> I have improved the (existing) comment in v40 [1].
>

One more thing related to this code:
pgoutput_row_filter()
{
..
+ if (!entry->rowfilter_valid)
{
..
+ oldctx = MemoryContextSwitchTo(CacheMemoryContext);
+ tupdesc = CreateTupleDescCopy(tupdesc);
+ entry->scantuple = MakeSingleTupleTableSlot(tupdesc, &TTSOpsHeapTuple);
+ MemoryContextSwitchTo(oldctx);
..
}

Why do we need to initialize scantuple here unless we are sure that
the row filter is going to get associated with this relentry? I think
when there is no row filter then this allocation is not required.

-- 
With Regards,
Amit Kapila.