RE: row filtering for logical replication

Wei Wang (Fujitsu) <wangw.fnst@fujitsu.com>

From: "wangw.fnst@fujitsu.com" <wangw.fnst@fujitsu.com>
To: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Peter Smith <smithpb2250@gmail.com>, Euler Taveira <euler@eulerto.com>, Greg Nancarrow <gregn4422@gmail.com>, vignesh C <vignesh21@gmail.com>, Ajin Cherian <itsajin@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: 2021-12-30T08:57:38Z
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 28, 2021 9:03 PM houzj.fnst@fujitsu.com <houzj.fnst@fujitsu.com> wrote:
> Attach a top up patch 0004 which did the above changes.

A few comments about v55-0001 and v55-0002.
v55-0001
1.
There is a typo at the last sentence of function(rowfilter_walker)'s comment. 
   * (b) a user-defined function can be used to access tables which could have
   * unpleasant results because a historic snapshot is used. That's why only
-  * non-immutable built-in functions are allowed in row filter expressions.
+ * immutable built-in functions are allowed in row filter expressions.

2.
There are two if statements at the end of fetch_remote_table_info.
+			if (!isnull)
+				*qual = lappend(*qual, makeString(TextDatumGetCString(rf)));
+
+			ExecClearTuple(slot);
+
+			/* Ignore filters and cleanup as necessary. */
+			if (isnull)
+			{
+				if (*qual)
+				{
+					list_free_deep(*qual);
+					*qual = NIL;
+				}
+				break;
+			}
What about using the format like following:
if (!isnull)
    ...
else
    ...


v55-0002
In function pgoutput_row_filter_init, I found almost whole function is in the if
statement written like this:
static void
pgoutput_row_filter_init()
{
    Variable declaration and initialization;
    if (!entry->exprstate_valid)
    {
        ......
    }
}
What about changing this if statement like following:
if (entry->exprstate_valid)
	return;


Regards,
Wang wei