Horton

Re: row filtering for logical replication

Euler Taveira <euler@eulerto.com>

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From: "Euler Taveira" <euler@eulerto.com>
To: pgsql-hackers@lists.postgresql.org
Cc: onderkalaci@gmail.com, david@pgmasters.net, "Craig Ringer" <craig@2ndquadrant.com>, "Tomas Vondra" <tomas.vondra@2ndquadrant.com>, "Michael Paquier" <michael@paquier.xyz>, "Amit Langote" <amitlangote09@gmail.com>, "movead li" <movead.li@highgo.ca>
Date: 2021-02-01T00:23:04Z
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

Attachments

On Mon, Mar 16, 2020, at 10:58 AM, David Steele wrote:
> Please submit to a future CF when a new patch is available.
Hi,

This is another version of the row filter patch. Patch summary:

0001: refactor to remove dead code
0002: grammar refactor for row filter
0003: core code, documentation, and tests
0004: psql code
0005: pg_dump support
0006: debug messages (only for test purposes)
0007: measure row filter overhead (only for test purposes)

From the previous version I incorporated Amit's suggestions [1], improve documentation and tests. I refactored to code to make it simple to read (break the row filter code into functions). This new version covers the new parameter publish_via_partition_root that was introduced (cf 83fd4532a7).

Regarding function prohibition, I wouldn't like to open a can of worms (see previous discussions in this thread). Simple expressions covers most of the use cases that I worked with until now. This prohibition can be removed in another patch after some careful analysis.

I did some limited tests and didn't observe some excessive CPU usage while testing this patch tough I agree with Andres that retain some expression context into a cache would certainly speed up this piece of code. I measured the row filter overhead in my i7 (see 0007)  and got:

mean:           92.49 us
stddev:         32.63 us
median:         83.45 us
min-max:        [11.13 .. 2731.55] us
percentile(95): 117.76 us

[1] https://www.postgresql.org/message-id/CA%2BHiwqG3Jz-cRS%3D4gqXmZDjDAi%3D%3D19GvrFCCqAawwHcOCEn4fQ%40mail.gmail.com


--
Euler Taveira
EnterpriseDB:  https://www.enterprisedb.com/