Re: row filtering for logical replication

Greg Nancarrow <gregn4422@gmail.com>

From: Greg Nancarrow <gregn4422@gmail.com>
To: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>
Cc: Amit Kapila <amit.kapila16@gmail.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: 2022-01-21T09:25:52Z
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, Jan 20, 2022 at 12:12 PM houzj.fnst@fujitsu.com
<houzj.fnst@fujitsu.com> wrote:
>
> Attach the V68 patch set which addressed the above comments and changes.
> The version patch also fix the error message mentioned by Greg[1]
>

Some review comments for the v68 patch, mostly nitpicking:

(1) Commit message
Minor suggested updates:

BEFORE:
Allow specifying row filter for logical replication of tables.
AFTER:
Allow specifying row filters for logical replication of tables.

BEFORE:
If you choose to do the initial table synchronization, only data that
satisfies the row filters is pulled by the subscriber.
AFTER:
If you choose to do the initial table synchronization, only data that
satisfies the row filters is copied to the subscriber.


src/backend/executor/execReplication.c

(2)

BEFORE:
+ * table does not publish UPDATES or DELETES.
AFTER:
+ * table does not publish UPDATEs or DELETEs.


src/backend/replication/pgoutput/pgoutput.c

(3) pgoutput_row_filter_exec_expr
pgoutput_row_filter_exec_expr() returns false if "isnull" is true,
otherwise (if "isnull" is false) returns the value of "ret"
(true/false).
So the following elog needs to be changed (Peter Smith previously
pointed this out, but it didn't get completely changed):

BEFORE:
+ elog(DEBUG3, "row filter evaluates to %s (isnull: %s)",
+ DatumGetBool(ret) ? "true" : "false",
+ isnull ? "true" : "false");
AFTER:
+ elog(DEBUG3, "row filter evaluates to %s (isnull: %s)",
+ isnull ? "false" : DatumGetBool(ret) ? "true" : "false",
+ isnull ? "true" : "false");


(4) pgoutput_row_filter_init

BEFORE:
+  * we don't know yet if there is/isn't any row filters for this relation.
AFTER:
+  * we don't know yet if there are/aren't any row filters for this relation.

BEFORE:
+  * necessary at all. This avoids us to consume memory and spend CPU cycles
+  * when we don't need to.
AFTER:
+  * necessary at all. So this allows us to avoid unnecessary memory
+  * consumption and CPU cycles.

(5) pgoutput_row_filter

BEFORE:
+ * evaluates the row filter for that tuple and return.
AFTER:
+ * evaluate the row filter for that tuple and return.


Regards,
Greg Nancarrow
Fujitsu Australia