Horton

Re: row filtering for logical replication

Peter Smith <smithpb2250@gmail.com>

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From: Peter Smith <smithpb2250@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Ajin Cherian <itsajin@gmail.com>, "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>, vignesh C <vignesh21@gmail.com>, Greg Nancarrow <gregn4422@gmail.com>, "tanghy.fnst@fujitsu.com" <tanghy.fnst@fujitsu.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>, Amit Langote <amitlangote09@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-12-01T21:47:40Z
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, Nov 25, 2021 at 12:03 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Tue, Nov 23, 2021 at 4:58 PM Ajin Cherian <itsajin@gmail.com> wrote:
> >
> > Attaching a new patchset v41 which includes changes by both Peter and myself.
> >
> > Patches v40-0005 and v40-0006 have been merged to create patch
> > v41-0005 which reduces the patches to 6 again.
> > This patch-set contains changes addressing the following review comments:
> >
> > On Mon, Nov 15, 2021 at 5:48 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > >
> > > What I meant was that with this new code we have regressed the old
> > > behavior. Basically, imagine a case where no filter was given for any
> > > of the tables. Then after the patch, we will remove all the old tables
> > > whereas before the patch it will remove the oldrels only when they are
> > > not specified as part of new rels. If you agree with this, then we can
> > > retain the old behavior and for the new tables, we can always override
> > > the where clause for a SET variant of command.
> >
> > Fixed and modified the behaviour to match with what the schema patch
> > implemented.
> >
>
> +
> + /*
> + * If the new relation or the old relation has a where clause,
> + * we need to remove it so that it can be added afresh later.
> + */
> + if (RelationGetRelid(newpubrel->relation) == oldrelid &&
> + newpubrel->whereClause == NULL && rfisnull)
>
> Can't we use _equalPublicationTable() here? It compares the whereClause as well.
>

Fixed in v44 [1]

> Few more comments:
> =================
> 0001
...

.
> 3. In the function header comment of rowfilter_walker, you mentioned
> the simple expressions allowed but we should write why we are doing
> so. It has been discussed in detail in various emails in this thread.
> AFAIR, below are the reasons:
> A. We don't want to allow user-defined functions or operators because
> (a) if the user drops such a function/operator or if there is any
> other error via that function, the walsender won't be able to recover
> from such an error even if we fix the function's problem because it
> uses a historic snapshot to access row-filter; (b) any other table
> could be accessed via a function which won't work because of historic
> snapshots in logical decoding environment.
>
> B. We don't allow anything other immutable built-in functions as those
> can access database and would lead to the problem (b) mentioned in the
> previous paragraph.
>

Updated comment in v44 [1]

> Don't we need to check for user-defined types similar to user-defined
> functions and operators? If not why?

Fixed in v44 [1]

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[1] https://www.postgresql.org/message-id/CAHut%2BPtjxzedJPbSZyb9pd72%2BUrGEj6HagQQbCdO0YJvr7OyJg%40mail.gmail.com

Kind Regards,
Peter Smith.
Fujitsu Australia