Horton

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

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: Dilip Kumar <dilipbalaut@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: 2020-07-25T11:38:03Z
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.

On Fri, Jul 24, 2020 at 7:17 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> Your changes look fine to me.  Additionally, I have changed a test
> case of getting the streaming changes in 0002.  Instead of just
> showing the count, I am showing that the transaction is actually
> streaming.
>

If you want to show the changes then there is no need to display 157
rows probably a few (10-15) should be sufficient.  If we can do that
by increasing the size of the row then good, otherwise, I think it is
better to retain the test to display the count.

Today, I have again looked at the first patch
(v42-0001-Extend-the-logical-decoding-output-plugin-API-wi) and didn't
find any more problems with it so planning to commit the same unless
you or someone else want to add more to it.   Just for ease of others,
"the next patch extends the logical decoding output plugin API with
stream methods".   It adds seven methods to the output plugin API,
adding support for streaming changes for large in-progress
transactions. The methods are stream_start, stream_stop, stream_abort,
stream_commit, stream_change, stream_message, and stream_truncate.
Most of this is a simple extension of the existing methods, with the
semantic difference that the transaction (or subtransaction) is
incomplete and may be aborted later (which is something the regular
API does not really need to deal with).

This also extends the 'test_decoding' plugin, implementing these new
stream methods.  The stream_start/start_stop are used to demarcate a
chunk of changes streamed for a particular toplevel transaction.

This commit simply adds these new APIs and the upcoming patch to
"allow the streaming mode in ReorderBuffer" will use these APIs.

-- 
With Regards,
Amit Kapila.