Horton

Re: row filtering for logical replication

David Fetter <david@fetter.org>

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From: David Fetter <david@fetter.org>
To: Euler Taveira <euler@timbira.com.br>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2018-03-01T16:06:42Z
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 Thu, Mar 01, 2018 at 12:41:04PM -0300, Euler Taveira wrote:
> 2018-02-28 21:47 GMT-03:00 David Fetter <david@fetter.org>:
> > I noticed that the WHERE clause applies to all tables in the
> > publication.  Is that actually the right thing?  I'm thinking of a
> > case where we have foo(id, ...) and bar(foo_id, ....).  To slice that
> > correctly, we'd want to do the ids in the foo table and the foo_ids in
> > the bar table.  In the system as written, that would entail, at least
> > potentially, writing a lot of publications by hand.
> >
> I didn't make it clear in my previous email and I think you misread
> the attached docs. Each table can have an optional WHERE clause. I'll
> made it clear when I rewrite the tests. Something like:

Sorry I misunderstood.

> CREATE PUBLICATION tap_pub FOR TABLE tab_rowfilter_1 WHERE (a > 1000
> AND b <> 'filtered'), tab_rowfilter_2 WHERE (c % 2 = 0),
> tab_rowfilter_3;

That's great!

> Such syntax will not block another future feature that will publish
> only few columns of the table.
> 
> > I also noticed that in psql, \dRp+ doesn't show the WHERE clause,
> > which it probably should.
> >
> Yea, it could be added be I'm afraid of such long WHERE clauses.

I think of + as signifying, "I am ready to get a LOT of output in
order to see more detail."  Perhaps that's just me.

> > Does it need regression tests?
> >
> I included some tests just to demonstrate the feature but I'm
> planning to add a separate test file for it.

Excellent. This feature looks like a nice big chunk of the user-space
infrastructure needed for sharding, among other things.

Best,
David.
-- 
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778

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