Horton

Re: row filtering for logical replication

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>
Cc: Peter Smith <smithpb2250@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, 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: 2022-01-26T10:56:31Z
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 26, 2022 at 8:37 AM houzj.fnst@fujitsu.com
<houzj.fnst@fujitsu.com> wrote:
>
> On Monday, January 24, 2022 4:38 PM Peter Smith <smithpb2250@gmail.com> wrote:
> >
> >
> > 3. src/backend/utils/cache/relcache.c - RelationBuildPublicationDesc
> >
> > +RelationBuildPublicationDesc(Relation relation)
> >  {
> >   List    *puboids;
> >   ListCell   *lc;
> >   MemoryContext oldcxt;
> >   Oid schemaid;
> > - PublicationActions *pubactions = palloc0(sizeof(PublicationActions));
> > + List    *ancestors = NIL;
> > + Oid relid = RelationGetRelid(relation); AttrNumber invalid_rfcolnum =
> > + InvalidAttrNumber; PublicationDesc *pubdesc =
> > + palloc0(sizeof(PublicationDesc)); PublicationActions *pubactions =
> > + &pubdesc->pubactions;
> > +
> > + pubdesc->rf_valid_for_update = true;
> > + pubdesc->rf_valid_for_delete = true;
> >
> > IMO it wold be better to change the "sense" of those variables.
> > e.g.
> >
> > "rf_valid_for_update" --> "rf_invalid_for_update"
> > "rf_valid_for_delete" --> "rf_invalid_for_delete"
> >
> > That way they have the same 'sense' as the AttrNumbers so it all reads better to
> > me.
> >
> > Also, it means no special assignment is needed because the palloc0 will set
> > them correctly
>
> Think again, I am not sure it's better to have an invalid_... flag.
> It seems more natural to have a valid_... flag.
>

Can't we do without these valid_ flags? AFAICS, if we check for
"invalid_" attributes, it should serve our purpose because those can
have some attribute number only when the row filter contains some
column that is not part of RI. A few possible optimizations in
RelationBuildPublicationDesc:

a. It calls contain_invalid_rfcolumn with pubid and then does cache
lookup to again find a publication which its only caller has access
to, so can't we pass the same?
b. In RelationBuildPublicationDesc(), we call
GetRelationPublications() to get the list of publications and then
process those publications. I think if none of the publications has
row filter and the relation has replica identity then we don't need to
build the descriptor at all. If we do this optimization inside
RelationBuildPublicationDesc, we may want to rename function as
CheckAndBuildRelationPublicationDesc or something like that?

-- 
With Regards,
Amit Kapila.