Horton

Re: row filtering for logical replication

Peter Smith <smithpb2250@gmail.com>

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From: Peter Smith <smithpb2250@gmail.com>
To: "wangw.fnst@fujitsu.com" <wangw.fnst@fujitsu.com>
Cc: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>, Amit Kapila <amit.kapila16@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: 2022-01-07T04:38:09Z
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 Wed, Jan 5, 2022 at 1:05 PM wangw.fnst@fujitsu.com
<wangw.fnst@fujitsu.com> wrote:
>
> On Thu, Jan 4, 2022 at 00:54 PM Peter Smith <smithpb2250@gmail.com> wrote:
> > Modified in v58 [1] as suggested
> Thanks for updating the patches.
> A few comments about v58-0001 and v58-0002.
>
> v58-0001
> 1.
> How about modifying the following loop in copy_table by using for_each_from
> instead of foreach?
> Like the invocation of for_each_from in function get_rule_expr.
> from:
>                 if (qual != NIL)
>                 {
>                         ListCell   *lc;
>                         bool            first = true;
>
>                         appendStringInfoString(&cmd, " WHERE ");
>                         foreach(lc, qual)
>                         {
>                                 char       *q = strVal(lfirst(lc));
>
>                                 if (first)
>                                         first = false;
>                                 else
>                                         appendStringInfoString(&cmd, " OR ");
>                                 appendStringInfoString(&cmd, q);
>                         }
>                         list_free_deep(qual);
>                 }
> change to:
>                 if (qual != NIL)
>                 {
>                         ListCell   *lc;
>                         char       *q = strVal(linitial(qual));
>
>                         appendStringInfo(&cmd, " WHERE %s", q);
>                         for_each_from(lc, qual, 1)
>                         {
>                                 q = strVal(lfirst(lc));
>                                 appendStringInfo(&cmd, " OR %s", q);
>                         }
>                         list_free_deep(qual);
>                 }
>
> 2.
> I find the API of get_rel_sync_entry is modified.
> -get_rel_sync_entry(PGOutputData *data, Oid relid)
> +get_rel_sync_entry(PGOutputData *data, Relation relation)
> It looks like just moving the invocation of RelationGetRelid from outside into
> function get_rel_sync_entry. I am not sure whether this modification is
> necessary to this feature or not.
>
> v58-0002
> 1.
> In function pgoutput_row_filter_init, if no_filter is set, I think we do not
> need to add row filter to list(rfnodes).
> So how about changing three conditions when add row filter to rfnodes like this:
> -                                       if (pub->pubactions.pubinsert)
> +                                       if (pub->pubactions.pubinsert && !no_filter[idx_ins])
>                                         {
>                                                 rfnode = stringToNode(TextDatumGetCString(rfdatum));
>                                                 rfnodes[idx_ins] = lappend(rfnodes[idx_ins], rfnode);
>                                         }
>

I think currently there is no harm done with the current code because
even there was no_filter[xxx] then any gathered rfnodes[xxx] will be
later cleaned up and ignored anyway, so this change is not really
necessary.

OTOH your suggestion could be a tiny bit more efficient for some cases
if there are many publications. so LGTM.

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