Horton

Re: row filtering for logical replication

Ajin Cherian <itsajin@gmail.com>

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From: Ajin Cherian <itsajin@gmail.com>
To: Greg Nancarrow <gregn4422@gmail.com>
Cc: Dilip Kumar <dilipbalaut@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, Euler Taveira <euler@eulerto.com>, Peter Smith <smithpb2250@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>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Amit Langote <amitlangote09@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-10-20T02:58:56Z
Lists: pgsql-hackers

Commits

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  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

Attachments

On Fri, Oct 15, 2021 at 3:30 PM Greg Nancarrow <gregn4422@gmail.com> wrote:
>
> On Wed, Oct 13, 2021 at 10:00 PM Ajin Cherian <itsajin@gmail.com> wrote:
> >
> > I have made the change to use the virtual slot for expression
> > evaluation and avoided tuple deformation.
> >
>
> I started looking at the v32-0006 patch and have some initial comments.
> Shouldn't old_slot, new_slot and tmp_new_slot be cached in the
> RelationSyncEntry, similar to scantuple?
> Currently, these slots are always getting newly allocated each call to
> pgoutput_row_filter_update() - and also, seemingly never deallocated.
> We previously found that allocating slots each time for each row
> filtered (over 1000s of rows) had a huge performance overhead.
> As an example, scantuple was originally newly allocated each row
> filtered, and to filter 1,000,000 rows in a test case it was taking 40
> seconds. Caching the allocation in RelationSyncEntry reduced it down
> to about 5 seconds.

Thanks for the comment, I have modified patch 6 to cache old_tuple,
new_tuple and tmp_new_tuple.

On Tue, Oct 12, 2021 at 1:37 AM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> +        if ((att->attlen == -1 &&
> VARATT_IS_EXTERNAL_ONDISK(tmp_new_slot->tts_values[i])) &&
> +                (!old_slot->tts_isnull[i] &&
> +                    !(VARATT_IS_EXTERNAL_ONDISK(old_slot->tts_values[i]))))
> +        {
> +            tmp_new_slot->tts_values[i] = old_slot->tts_values[i];
> +            newtup_changed = true;
> +        }
>
> If the attribute is stored EXTERNAL_ONDIS on the new tuple and it is
> not null in the old tuple then it must be logged completely in the old
> tuple, so instead of checking
> !(VARATT_IS_EXTERNAL_ONDISK(old_slot->tts_values[i]), it should be
> asserted,

Sorry, I missed this  in my last update
For this to be true, shouldn't the fix in [1] be committed? I will
change this once that change is committed.

[1] - https://www.postgresql.org/message-id/OS0PR01MB611342D0A92D4F4BF26C0F47FB229@OS0PR01MB6113.jpnprd01.prod.outlook.com

regards,
Ajin Cherian
Fujitsu Australia