RE: row filtering for logical replication

tanghy <tanghy.fnst@fujitsu.com>

From: "tanghy.fnst@fujitsu.com" <tanghy.fnst@fujitsu.com>

To: Peter Smith <smithpb2250@gmail.com>, Ajin Cherian <itsajin@gmail.com>

Cc: Amit Kapila <amit.kapila16@gmail.com>, "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>, vignesh C <vignesh21@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: 2021-11-30T03:49:14Z

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 →

Release cache tuple when no longer needed
- ed0fbc8e5ac9 15.0 landed
Add some additional tests for row filters in logical replication.
- ceb57afd3ce1 15.0 landed
Fix one of the tests introduced in commit 52e4f0cd47.
- cfb4e209ec15 15.0 landed
Allow specifying row filters for logical replication of tables.
- 52e4f0cd472d 15.0 landed
Move scanint8() to numutils.c
- cfc7191dfea3 15.0 cited
Replace Test::More plans with done_testing
- 549ec201d613 15.0 cited
Reduce relcache access in WAL sender streaming logical changes
- 6ce16088bfed 15.0 cited
Small cleanups related to PUBLICATION framework code
- c9105dd3660f 15.0 cited
Add a view to show the stats of subscription workers.
- 8d74fc96db5f 15.0 cited
Allow publishing the tables of schema.
- 5a2832465fd8 15.0 cited
Doc: improve documentation of CREATE/ALTER SUBSCRIPTION.
- 1882d6cca161 15.0 cited
Add PublicationTable and PublicationRelInfo structs
- 0c6828fa987b 15.0 cited
Remove unused argument "txn" in maybe_send_schema().
- 93d573d86571 15.0 cited
Add prepare API support for streaming transactions in logical replication.
- 63cf61cdeb7b 15.0 cited
Unify PostgresNode's new() and get_new_node() methods
- 201a76183e20 15.0 cited
Use l*_node() family of functions where appropriate
- 2b00db4fb0c7 15.0 cited
Add support for prepared transactions to built-in logical replication.
- a8fd13cab0ba 15.0 cited
Restore the portal-level snapshot after procedure COMMIT/ROLLBACK.
- ef9480509622 11.13 cited
Rename a parse node to be more general
- 91d1f2d30210 14.0 landed
Remove unused column atttypmod from initial tablesync query
- 4ad31bb2ef25 14.0 landed
SEARCH and CYCLE clauses
- 3696a600e229 14.0 cited

On Thursday, November 25, 2021 11:22 AM Peter Smith <smithpb2250@gmail.com> wrote:
> 
> Thanks for all the review comments so far! We are endeavouring to keep
> pace with them.
> 
> All feedback is being tracked and we will fix and/or reply to everything ASAP.
> 
> Meanwhile, PSA the latest set of v42* patches.
> 
> This version was mostly a patch restructuring exercise but it also
> addresses some minor review comments in passing.
> 

Thanks for your patch.
I have two comments on the document in 0001 patch.

1.
+   New row is used and it contains all columns. A <literal>NULL</literal> value
+   causes the expression to evaluate to false; avoid using columns without

I don't quite understand this sentence 'A NULL value causes the expression to evaluate to false'. 
The expression contains NULL value can also return true. Could you be more specific?

For example:

postgres=# select null or true;
 ?column?
----------
 t
(1 row)

2.
+   at all then all other filters become redundant. If the subscriber is a
+   <productname>PostgreSQL</productname> version before 15 then any row filtering
+   is ignored.

If the subscriber is a PostgreSQL version before 15, it seems row filtering will
be ignored only when copying initial data, the later changes will not be ignored in row
filtering. Should we make it clear in document?

Regards,
Tang