Horton

Re: row filtering for logical replication

Peter Smith <smithpb2250@gmail.com>

View thread
From: Peter Smith <smithpb2250@gmail.com>
To: Dilip Kumar <dilipbalaut@gmail.com>
Cc: Ajin Cherian <itsajin@gmail.com>, "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>, Greg Nancarrow <gregn4422@gmail.com>, Euler Taveira <euler@eulerto.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 Kapila <amit.kapila16@gmail.com>, Amit Langote <amitlangote09@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-11-18T05:46:30Z
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, Nov 15, 2021 at 8:14 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> On Fri, Nov 12, 2021 at 3:49 PM Ajin Cherian <itsajin@gmail.com> wrote:
> >
> > Attaching version 39-
> >
>
> Some comments on 0006
>
> --
...
> --
>
> Looking further, I realized that "logicalrep_write_tuple" and
> "logicalrep_write_tuple_cached" are completely duplicate except first
> one is calling "heap_deform_tuple" and then using local values[] array
> and the second one is directly using the slot->values[] array, so in
> fact we can pass this also as a parameter or we can put just one if
> check the populate the values[] and null array, so if it is cached we
> will point directly to the slot->values[] otherwise
> heap_deform_tuple(), I think this should be just one simple check.

Fixed in v40 [1]

> --
> +
> +/*
> + * Change is checked against the row filter, if any.
> + *
> + * If it returns true, the change is replicated, otherwise, it is not.
> + */
> +static bool
> +pgoutput_row_filter_virtual(Relation relation, TupleTableSlot *slot,
> RelationSyncEntry *entry)
>
> IMHO, the comments should explain how it is different from the
> pgoutput_row_filter function.  Also comments are saying "If it returns
> true, the change is replicated, otherwise, it is not" which is not
> exactly true for this function, I mean based on that the caller will
> change the action.  So I think it is enough to say what this function
> is doing but not required to say what the caller will do based on what
> this function returns.

Fixed in v40 [1].

>
>
> --
>
> +    for (i = 0; i < desc->natts; i++)
> +    {
> +        Form_pg_attribute att = TupleDescAttr(desc, i);
> +
> +        /* if the column in the new_tuple is null, nothing to do */
> +        if (tmp_new_slot->tts_isnull[i])
> +            continue;
>
> Put some comments over this loop about what it is trying to do, and
> overall I think there are not sufficient comments in the
> pgoutput_row_filter_update_check function.

Fixed in v40 [1].

>
> --
> +        /*
> +          * Unchanged toasted replica identity columns are
> +          * only detoasted in the old tuple, copy this over to the newtuple.
> +          */
> +        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]))))
>
> Is it ever possible that if the attribute is not NULL in the old slot
> still it is stored as VARATT_IS_EXTERNAL_ONDISK? I think no, so
> instead of adding
> this last condition in check it should be asserted inside the if check.
>

Fixed in v40 [1]

-----
[1] https://www.postgresql.org/message-id/CAHut%2BPv-D4rQseRO_OzfEz2dQsTKEnKjBCET9Z-iJppyT1XNMQ%40mail.gmail.com

Kind Regards,
Peter Smith.
Fujitsu Australia