Re: row filtering for logical replication

Amit Kapila <amit.kapila16@gmail.com>

From: Amit Kapila <amit.kapila16@gmail.com>
To: Greg Nancarrow <gregn4422@gmail.com>
Cc: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Peter Smith <smithpb2250@gmail.com>, "tanghy.fnst@fujitsu.com" <tanghy.fnst@fujitsu.com>, Euler Taveira <euler@eulerto.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: 2022-01-24T09:32:17Z
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 Mon, Jan 24, 2022 at 1:19 PM Greg Nancarrow <gregn4422@gmail.com> wrote:
>
> On Mon, Jan 24, 2022 at 5:09 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > But that is not what I am seeing in Logs with a test case where the
> > row filter column has NULL values. Could you please try that see what
> > is printed in LOG?
> >
> > You can change the code to make the elevel as LOG to get the results
> > easily. The test case I tried is as follows:
> > Node-1:
> > postgres=# create table t1(c1 int, c2 int);
> > CREATE TABLE
> > postgres=# create publication pub for table t1 WHERE (c1 > 10);
> > CREATE PUBLICATION
> >
> > Node-2:
> > postgres=# create table t1(c1 int, c2 int);
> > CREATE TABLE
> > postgres=# create subscription sub connection 'dbname=postgres' publication pub;
> > NOTICE:  created replication slot "sub" on publisher
> > CREATE SUBSCRIPTION
> >
> > After this on publisher-node, I see the LOG as "LOG:  row filter
> > evaluates to false (isnull: true)". I have verified that in the code
> > as well (in slot_deform_heap_tuple), we set the value as 0 for isnull
> > which matches above observation.
> >
>
> There are obviously multiple code paths under which a column can end up as NULL.
> Doing one NULL-column test case, and finding here that
> "DatumGetBool(ret)" is "false" when "isnull" is true, doesn't prove it
> will be like that for ALL possible cases.
>

Sure, I just wanted to see the particular test which leads to failure
so that I or others can know (or debug) why in some cases it behaves
differently. Anyway, for others, the below test can show the results:

CREATE TABLE tab_rowfilter_1 (a int primary key, b text);
alter table tab_rowfilter_1 replica identity full ;
INSERT INTO tab_rowfilter_1 (a, b) VALUES (1600, 'test 1600');
CREATE PUBLICATION pub FOR TABLE tab_rowfilter_1 WHERE (a > 1000 AND b
<> 'filtered');

UPDATE tab_rowfilter_1 SET b = NULL WHERE a = 1600;

So, we can change this DEBUG log.

-- 
With Regards,
Amit Kapila.