Re: row filtering for logical replication

Peter Smith <smithpb2250@gmail.com>

From: Peter Smith <smithpb2250@gmail.com>
To: Amit Kapila <amit.kapila16@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: 2021-11-18T21:46:18Z
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 4:32 PM Peter Smith <smithpb2250@gmail.com> wrote:
>
> On Mon, Nov 15, 2021 at 9:31 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > On Wed, Nov 10, 2021 at 12:36 PM Peter Smith <smithpb2250@gmail.com> wrote:
> > >
> > > On Mon, Nov 8, 2021 at 5:53 PM houzj.fnst@fujitsu.com
> > > <houzj.fnst@fujitsu.com> wrote:
> > > >
> > > > 3) v37-0005
> > > >
> > > > - no parse nodes of any kind other than Var, OpExpr, Const, BoolExpr, FuncExpr
> > > >
> > > > I think there could be other node type which can also be considered as simple
> > > > expression, for exmaple T_NullIfExpr.
> > >
> > > The current walker restrictions are from a previously agreed decision
> > > by Amit/Tomas [1] and from an earlier suggestion from Andres [2] to
> > > keep everything very simple for a first version.
> > >
> > > Yes, you are right, there might be some additional node types that
> > > might be fine, but at this time I don't want to add anything different
> > > without getting their approval to do so. Anyway, additions like this
> > > are all candidates for a future version of this row-filter feature.
> > >
> >
> > I think we can consider T_NullIfExpr unless you see any problem with the same.
>
> Added in v40 [1]
>

I've noticed that row-filters that are testing NULL cannot pass the
current expression validation restrictions.

e.g.1
test_pub=# create publication ptest for table t1 where (a is null);
ERROR:  invalid publication WHERE expression for relation "t1"
HINT:  only simple expressions using columns, constants and immutable
system functions are allowed

e.g.2
test_pub=# create publication ptest for table t1 where (a is not null);
ERROR:  invalid publication WHERE expression for relation "t1"
HINT:  only simple expressions using columns, constants and immutable
system functions are allowed

So I think it would be useful to permit the NullTest also. Is it OK?

------
KInd Regards,
Peter Smith.
Fujitsu Australia