Horton

Re: PATCH: logical_work_mem and logical streaming of large in-progress transactions

Dilip Kumar <dilipbalaut@gmail.com>

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From: Dilip Kumar <dilipbalaut@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Erik Rijkers <er@xs4all.nl>, Kuntal Ghosh <kuntalghosh.2007@gmail.com>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Michael Paquier <michael@paquier.xyz>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2020-08-04T07:11:46Z
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. Tighten the concurrent abort check during decoding.

  2. Improve hash_create()'s API for some added robustness.

  3. Use HASH_BLOBS for xidhash.

  4. Fix initialization of RelationSyncEntry for streaming transactions.

  5. Remove unused function declaration in logicalproto.h.

  6. Add additional tests to test streaming of in-progress transactions.

  7. Fix inline marking introduced in commit 464824323e.

  8. Add support for streaming to built-in logical replication.

  9. Fix the SharedFileSetUnregister API.

  10. Fix comment in procarray.c

  11. Suppress compiler warning in non-cassert builds.

  12. Extend the BufFile interface.

  13. Mark a few logical decoding related variables with PGDLLIMPORT.

  14. Implement streaming mode in ReorderBuffer.

  15. Extend the logical decoding output plugin API with stream methods.

  16. WAL Log invalidations at command end with wal_level=logical.

  17. Immediately WAL-log subtransaction and top-level XID association.

  18. Allow logical replication to transfer data in binary format.

  19. Only superuser can set sslcert/sslkey in postgres_fdw user mappings

  20. Track statistics for spilling of changes from ReorderBuffer.

  21. Add logical_decoding_work_mem to limit ReorderBuffer memory usage.

  22. logical decoding: process ASSIGNMENT during snapshot build

  23. Emit invalidations to standby for transactions without xid.

Attachments

On Tue, Aug 4, 2020 at 10:12 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Wed, Jul 29, 2020 at 10:46 AM Dilip Kumar <dilipbalaut@gmail.com> wrote:
> >
> > Thanks, please find the rebased patch set.
> >
>
> Few comments on v44-0001-Implement-streaming-mode-in-ReorderBuffer:
> ============================================================
> 1.
> +-- streaming with subxact, nothing in main
> +BEGIN;
> +savepoint s1;
> +SELECT 'msg5' FROM pg_logical_emit_message(true, 'test', repeat('a', 50));
> +INSERT INTO stream_test SELECT repeat('a', 2000) || g.i FROM
> generate_series(1, 35) g(i);
> +TRUNCATE table stream_test;
> +rollback to s1;
> +INSERT INTO stream_test SELECT repeat('a', 10) || g.i FROM
> generate_series(1, 20) g(i);
> +COMMIT;
>
> Is the above comment true?  Because it seems to me that Insert is
> getting streamed in the main transaction.

Changed the comments.

> 2.
> +<programlisting>
> +postgres[33712]=#* SELECT * FROM
> pg_logical_slot_get_changes('test_slot', NULL, NULL, 'stream-changes',
> '1');
> +    lsn    | xid |                       data
> +-----------+-----+--------------------------------------------------
> + 0/16B21F8 | 503 | opening a streamed block for transaction TXN 503
> + 0/16B21F8 | 503 | streaming change for TXN 503
> + 0/16B2300 | 503 | streaming change for TXN 503
> + 0/16B2408 | 503 | streaming change for TXN 503
> + 0/16BEBA0 | 503 | closing a streamed block for transaction TXN 503
> + 0/16B21F8 | 503 | opening a streamed block for transaction TXN 503
> + 0/16BECA8 | 503 | streaming change for TXN 503
> + 0/16BEDB0 | 503 | streaming change for TXN 503
> + 0/16BEEB8 | 503 | streaming change for TXN 503
> + 0/16BEBA0 | 503 | closing a streamed block for transaction TXN 503
> +(10 rows)
> +</programlisting>
> + </para>
> +
>
> Is the above example correct?  Because we should include XID in the
> stream message only when include_xids option is specified.

include_xids is true if we don't set it to false explicitly

> 3.
>  /*
> - * Queue a change into a transaction so it can be replayed upon commit.
> + * Record the partial change for the streaming of in-progress transactions.  We
> + * can stream only complete changes so if we have a partial change like toast
> + * table insert or speculative then we mark such a 'txn' so that it can't be
> + * streamed.
>
> /speculative then/speculative insert then

Done

> 4.  I think we can explain the problems (like we can see the wrong
> tuple or see two versions of the same tuple or whatever else wrong can
> happen, if possible with some example) related to concurrent aborts
> somewhere in comments.

Done

-- 
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com