Re: row filtering for logical replication

Amit Kapila <amit.kapila16@gmail.com>

From: Amit Kapila <amit.kapila16@gmail.com>

To: Euler Taveira <euler@eulerto.com>

Cc: Peter Smith <smithpb2250@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>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Amit Langote <amitlangote09@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>

Date: 2021-08-25T08:31:37Z

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 →

Release cache tuple when no longer needed
- ed0fbc8e5ac9 15.0 landed
Add some additional tests for row filters in logical replication.
- ceb57afd3ce1 15.0 landed
Fix one of the tests introduced in commit 52e4f0cd47.
- cfb4e209ec15 15.0 landed
Allow specifying row filters for logical replication of tables.
- 52e4f0cd472d 15.0 landed
Move scanint8() to numutils.c
- cfc7191dfea3 15.0 cited
Replace Test::More plans with done_testing
- 549ec201d613 15.0 cited
Reduce relcache access in WAL sender streaming logical changes
- 6ce16088bfed 15.0 cited
Small cleanups related to PUBLICATION framework code
- c9105dd3660f 15.0 cited
Add a view to show the stats of subscription workers.
- 8d74fc96db5f 15.0 cited
Allow publishing the tables of schema.
- 5a2832465fd8 15.0 cited
Doc: improve documentation of CREATE/ALTER SUBSCRIPTION.
- 1882d6cca161 15.0 cited
Add PublicationTable and PublicationRelInfo structs
- 0c6828fa987b 15.0 cited
Remove unused argument "txn" in maybe_send_schema().
- 93d573d86571 15.0 cited
Add prepare API support for streaming transactions in logical replication.
- 63cf61cdeb7b 15.0 cited
Unify PostgresNode's new() and get_new_node() methods
- 201a76183e20 15.0 cited
Use l*_node() family of functions where appropriate
- 2b00db4fb0c7 15.0 cited
Add support for prepared transactions to built-in logical replication.
- a8fd13cab0ba 15.0 cited
Restore the portal-level snapshot after procedure COMMIT/ROLLBACK.
- ef9480509622 11.13 cited
Rename a parse node to be more general
- 91d1f2d30210 14.0 landed
Remove unused column atttypmod from initial tablesync query
- 4ad31bb2ef25 14.0 landed
SEARCH and CYCLE clauses
- 3696a600e229 14.0 cited

On Wed, Aug 25, 2021 at 10:57 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Wed, Aug 25, 2021 at 5:52 AM Euler Taveira <euler@eulerto.com> wrote:
> >
> > On Tue, Aug 24, 2021, at 4:46 AM, Peter Smith wrote:

> >
> > Anyway, I have implemented the suggested cache change because I agree
> > it is probably theoretically superior, even if in practice there is
> > almost no difference.
> >
> > I didn't inspect your patch carefully but it seems you add another List to
> > control this new cache mechanism. I don't like it. IMO if we can use the data
> > structures that we have now, let's implement your idea; otherwise, -1 for this
> > new micro optimization.
> >
>
> As mentioned above, without this we will invalidate many cached
> expressions even though it is not required. I don't deny that there
> might be a better way to achieve the same and if you or Peter have any
> ideas, I am all ears.
>

I see that the new list is added to store row_filter node which we
later use to compute expression. This is not required for invalidation
but for delaying the expression evaluation till it is required (for
example, for truncate, we may not need the row evaluation, so there is
no need to compute it). Can we try to postpone the syscache lookup to
a later stage when we are actually doing row_filtering? If we can do
that, then I think we can avoid having this extra list?

-- 
With Regards,
Amit Kapila.