Horton

RE: row filtering for logical replication

Zhijie Hou (Fujitsu) <houzj.fnst@fujitsu.com>

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From: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>
To: Andres Freund <andres@anarazel.de>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Peter Smith <smithpb2250@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Euler Taveira <euler@eulerto.com>, Greg Nancarrow <gregn4422@gmail.com>, vignesh C <vignesh21@gmail.com>, Ajin Cherian <itsajin@gmail.com>, "tanghy.fnst@fujitsu.com" <tanghy.fnst@fujitsu.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: 2022-02-01T03:57:30Z
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 Saturday, January 29, 2022 8:31 AM Andres Freund <andres@anarazel.de>
> wrote:
> >
> > Hi,
> >
> > Are there any recent performance evaluations of the overhead of row
> > filters? I think it'd be good to get some numbers comparing:
> 
> Thanks for looking at the patch! Will test it.
> 
> > >  		case REORDER_BUFFER_CHANGE_INSERT:
> > >  			{
> > > -				HeapTuple	tuple = &change->data.tp.newtuple->tuple;
> > > +				/*
> > > +				 * Schema should be sent before the logic that replaces the
> > > +				 * relation because it also sends the ancestor's relation.
> > > +				 */
> > > +				maybe_send_schema(ctx, change, relation, relentry);
> > > +
> > > +				new_slot = relentry->new_slot;
> > > +
> > > +				ExecClearTuple(new_slot);
> > > +				ExecStoreHeapTuple(&change->data.tp.newtuple->tuple,
> > > +								   new_slot, false);
> >
> > Why? This isn't free, and you're doing it unconditionally. I'd bet this alone is
> > noticeable slowdown over the current state.
>
> It was intended to avoid deform the tuple twice, once in row filter execution
> ,second time in logicalrep_write_tuple. But I will test the performance
> impact of this and improve this if needed.

I removed the unnecessary ExecClearTuple here, I think the ExecStoreHeapTuple
here doesn't allocate or free any memory and seems doesn't have a noticeable
impact from the perf result[1]. And we need this to avoid deforming the tuple
twice. So, it looks acceptable to me.

[1] 0.01%     0.00%  postgres  pgoutput.so         [.] ExecStoreHeapTuple@plt

Best regards,
Hou zj