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: Peter Smith <smithpb2250@gmail.com>
Cc: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, "tanghy.fnst@fujitsu.com" <tanghy.fnst@fujitsu.com>, Euler Taveira <euler@eulerto.com>, Greg Nancarrow <gregn4422@gmail.com>, vignesh C <vignesh21@gmail.com>, Ajin Cherian <itsajin@gmail.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: 2022-01-14T02:16:56Z
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 Fri, Jan 14, 2022 at 5:48 AM Peter Smith <smithpb2250@gmail.com> wrote:
>
> On Thu, Jan 13, 2022 at 5:49 PM Peter Smith <smithpb2250@gmail.com> wrote:
> >
> > 4. src/backend/replication/pgoutput/pgoutput.c - pgoutput_row_filter comments
> >
> > +
> > +/*
> > + * Change is checked against the row filter, if any.
> > + *
> > + * If it returns true, the change is replicated, otherwise, it is not.
> > + *
> > + * FOR INSERT: evaluates the row filter for new tuple.
> > + * FOR DELETE: evaluates the row filter for old tuple.
> > + * For UPDATE: evaluates the row filter for old and new tuple. If both
> > + * evaluations are true, it sends the UPDATE. If both evaluations are false, it
> > + * doesn't send the UPDATE. If only one of the tuples matches the row filter
> > + * expression, there is a data consistency issue. Fixing this issue requires a
> > + * transformation.
> > + *
> > + * Transformations:
> > + * Updates are transformed to inserts and deletes based on the
> > + * old tuple and new tuple. The new action is updated in the
> > + * action parameter. If not updated, action remains as update.
> > + *
> > + * Case 1: old-row (no match)    new-row (no match)  -> (drop change)
> > + * Case 2: old-row (no match)    new row (match)     -> INSERT
> > + * Case 3: old-row (match)       new-row (no match)  -> DELETE
> > + * Case 4: old-row (match)       new row (match)     -> UPDATE
> > + *
> > + * If the change is to be replicated this function returns true, else false.
> > + *
> > + * Examples:
> >
> > The function header comment says the same thing 2x about the return values.
> >
> > The 1st text "If it returns true, the change is replicated, otherwise,
> > it is not." should be replaced by the better wording of the 2nd text
> > ("If the change is to be replicated this function returns true, else
> > false."). Then, that 2nd text can be removed (from where it is later
> > in this same comment).
>
> Hi Hou-san, thanks for all the v64 updates!
>
> I think the above comment was only partly fixed.
>
> The v64-0001 comment still says:
> + * If it returns true, the change is replicated, otherwise, it is not.
>
...
...
>
> But maybe it is best to rearrange the whole thing like:
> "Returns true if the change is to be replicated, else false."
>

+1 to change as per this suggestion.

-- 
With Regards,
Amit Kapila.