Horton

Re: row filtering for logical replication

Greg Nancarrow <gregn4422@gmail.com>

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From: Greg Nancarrow <gregn4422@gmail.com>
To: Peter Smith <smithpb2250@gmail.com>
Cc: Ajin Cherian <itsajin@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, Euler Taveira <euler@eulerto.com>, "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>, vignesh C <vignesh21@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: 2021-12-15T04:50:04Z
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, Dec 13, 2021 at 8:49 PM Peter Smith <smithpb2250@gmail.com> wrote:
>
> PSA the v46* patch set.
>

0001

(1)

"If a subscriber is a pre-15 version, the initial table
synchronization won't use row filters even if they are defined in the
publisher."

Won't this lead to data inconsistencies or errors that otherwise
wouldn't happen? Should such subscriptions be allowed?

(2) In the 0001 patch comment, the term "publication filter" is used
in one place, and in others "row filter" or "row-filter".


src/backend/catalog/pg_publication.c
(3) GetTransformedWhereClause() is missing a function comment.

(4)
The following comment seems incomplete:

+ /* Fix up collation information */
+ whereclause = GetTransformedWhereClause(pstate, pri, true);


src/backend/parser/parse_relation.c
(5)
wording? consistent?
Shouldn't it be "publication WHERE expression" for consistency?

+ errmsg("publication row-filter WHERE invalid reference to table \"%s\"",
+ relation->relname),


src/backend/replication/logical/tablesync.c
(6)

(i) Improve wording:

BEFORE:
 /*
  * Get information about remote relation in similar fashion the RELATION
- * message provides during replication.
+ * message provides during replication. This function also returns the relation
+ * qualifications to be used in COPY command.
  */

AFTER:
 /*
- * Get information about remote relation in similar fashion the RELATION
- * message provides during replication.
+ * Get information about a remote relation, in a similar fashion to
how the RELATION
+ * message provides information during replication. This function
also returns the relation
+ * qualifications to be used in the COPY command.
  */

(ii) fetch_remote_table_info() doesn't currently account for ALL
TABLES and ALL TABLES IN SCHEMA.


src/backend/replication/pgoutput/pgoutput.c
(7) pgoutput_tow_filter()
I think that the "ExecDropSingleTupleTableSlot(entry->scantuple);" is
not needed in pgoutput_tow_filter() - I don't think it can be non-NULL
when entry->exprstate_valid is false

(8) I am a little unsure about this "combine filters on copy
(irrespective of pubaction)" functionality. What if a filter is
specified and the only pubaction is DELETE?


0002

src/backend/catalog/pg_publication.c
(1) rowfilter_walker()
One of the errdetail messages doesn't begin with an uppercase letter:

+   errdetail_msg = _("user-defined types are not allowed");


src/backend/executor/execReplication.c
(2) CheckCmdReplicaIdentity()

Strictly speaking, the following:

+ if (invalid_rfcolnum)

should be:

+ if (invalid_rfcolnum != InvalidAttrNumber)


0003

src/backend/replication/logical/tablesync.c
(1)
Column name in comment should be "puballtables" not "puballtable":

+ * If any publication has puballtable true then all row-filtering is

(2) pgoutput_row_filter_init()

There should be a space before the final "*/" (so the asterisks align).
Also, should say "... treated the same".

  /*
+ * If the publication is FOR ALL TABLES then it is treated same as if this
+ * table has no filters (even if for some other publication it does).
+ */


Regards,
Greg Nancarrow
Fujitsu Australia