Horton

Re: row filtering for logical replication

Peter Smith <smithpb2250@gmail.com>

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From: Peter Smith <smithpb2250@gmail.com>
To: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Ajin Cherian <itsajin@gmail.com>, Greg Nancarrow <gregn4422@gmail.com>, Dilip Kumar <dilipbalaut@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>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Amit Langote <amitlangote09@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-11-10T06:40:27Z
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, Nov 10, 2021 at 4:57 PM houzj.fnst@fujitsu.com
<houzj.fnst@fujitsu.com> wrote:
>
> On Wed, Nov 10, 2021 10:48 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > On Tue, Nov 9, 2021 at 2:22 PM houzj.fnst@fujitsu.com wrote:
> > >
> > > On Fri, Nov 5, 2021 4:49 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > > > On Fri, Nov 5, 2021 at 10:44 AM Peter Smith <smithpb2250@gmail.com> wrote:
> > > > >
> > > > > PSA new set of v37* patches.
> > > > 3.
> > > > - | ColId
> > > > + | ColId OptWhereClause
> > > >   {
> > > >   $$ = makeNode(PublicationObjSpec);
> > > >   $$->pubobjtype = PUBLICATIONOBJ_CONTINUATION;
> > > > - $$->name = $1;
> > > > + if ($2)
> > > > + {
> > > > + $$->pubtable = makeNode(PublicationTable); $$->pubtable->relation
> > > > + = makeRangeVar(NULL, $1, @1); $$->pubtable->whereClause = $2; }
> > > > + else { $$->name = $1; }
> > > >
> > > > Again this doesn't appear to be the right way. I think this should
> > > > be handled at a later point.
> > >
> > > I think the difficulty to handle this at a later point is that we need
> > > to make sure we don't lose the whereclause. Currently, we can only
> > > save the whereclause in PublicationTable structure and the
> > > PublicationTable is only used for TABLE, but '| ColId' can be used for
> > > either a SCHEMA or TABLE. We cannot distinguish the actual type at
> > > this stage, so we always need to save the whereclause if it's NOT NULL.
> > >
> >
> > I see your point. But, I think we can add some comments here indicating that
> > the user might have mistakenly given where clause with some schema which we
> > will identify later and give an appropriate error. Then, in
> > preprocess_pubobj_list(), identify if the user has given the where clause with
> > schema name and give an appropriate error.
> >
>
> OK, IIRC, in this approach, we need to set both $$->name and $$->pubtable in
> '| ColId OptWhereClause'. And In preprocess_pubobj_list, we can add some check
> if both name and pubtable is NOT NULL.
>
> the grammar code could be:
>
> | ColId OptWhereClause
> {
>         $$ = makeNode(PublicationObjSpec);
>         $$->pubobjtype = PUBLICATIONOBJ_CONTINUATION;
>
>         $$->name = $1;
> +       /* xxx */
> +       $$->pubtable = makeNode(PublicationTable);
> +       $$->pubtable->relation = makeRangeVar(NULL, $1, @1);
> +       $$->pubtable->whereClause = $2;
>         $$->location = @1;
> }
>
> preprocess_pubobj_list
> ...
> else if (pubobj->pubobjtype == PUBLICATIONOBJ_REL_IN_SCHEMA ||
> pubobj->pubobjtype == PUBLICATIONOBJ_CURRSCHEMA)
> {
>     ...
> +    if (pubobj->name &&
> +        (!pubobj->pubtable || !pubobj->pubtable->whereClause))
>             pubobj->pubobjtype = PUBLICATIONOBJ_REL_IN_SCHEMA;
>     else if (!pubobj->name && !pubobj->pubtable)
>             pubobj->pubobjtype = PUBLICATIONOBJ_CURRSCHEMA;
>     else
>             ereport(ERROR,
>                             errcode(ERRCODE_SYNTAX_ERROR),
>                             errmsg("invalid schema name at or near"),
>                             parser_errposition(pubobj->location));
> }
>

Hi Hou-san. Actually, I have already implemented this part according
to my understanding of Amit's suggestion and it seems to be working
well.

Please wait for v39-0001, then feel free to post review comments about
it if you think there are still problems.

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