Horton

Re: [HACKERS] logical decoding of two-phase transactions

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: Peter Smith <smithpb2250@gmail.com>
Cc: vignesh C <vignesh21@gmail.com>, "tanghy.fnst@fujitsu.com" <tanghy.fnst@fujitsu.com>, Ajin Cherian <itsajin@gmail.com>, Greg Nancarrow <gregn4422@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2021-07-11T10:20:10Z
Lists: pgsql-hackers

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On Fri, Jul 9, 2021 at 4:43 AM Peter Smith <smithpb2250@gmail.com> wrote:
>
> > The patch looks good to me, I don't have any comments.
>
> I tried the v95-0001 patch.
>
> - The patch applied cleanly and all build / testing was OK.
> - The documentation also builds OK.
> - I checked all v95-0001 / v93-0001 differences and found no problems.
> - Furthermore, I noted that v95-0001 patch is passing the cfbot [1].
>
> So this patch LGTM.
>

Thanks, I took another pass over it and made a few changes in docs and
comments. I am planning to push this next week sometime (by 14th July)
unless there are more comments from you or someone else. Just to
summarize, this patch will add support for prepared transactions to
built-in logical replication. To add support for streaming
transactions at prepare time into the
built-in logical replication, we need to do the following things: (a)
Modify the output plugin (pgoutput) to implement the new two-phase API
callbacks, by leveraging the extended replication protocol. (b) Modify
the replication apply worker, to properly handle two-phase
transactions by replaying them on prepare. (c) Add a new SUBSCRIPTION
option "two_phase" to allow users to enable
two-phase transactions. We enable the two_phase once the initial data
sync is over. Refer to comments atop worker.c in the patch and commit
message to see further details about this patch. After this patch,
there is a follow-up patch to allow streaming and two-phase options
together which I feel needs some more review and can be committed
separately.

-- 
With Regards,
Amit Kapila.

Commits

  1. Add prepare API support for streaming transactions in logical replication.

  2. Doc: minor improvements for logical replication protocol documentation.

  3. Fix test failure in 021_twophase.pl.

  4. Refactor to make common functions in proto.c and worker.c.

  5. Unify PostgresNode's new() and get_new_node() methods

  6. Fix potential buffer overruns in proto.c.

  7. Add support for prepared transactions to built-in logical replication.

  8. Refactor function parse_subscription_options.

  9. Allow enabling two-phase option via replication protocol.

  10. Don't use Asserts to check for violations of replication protocol.

  11. Improve psql tab completion for options of subcriptions and publications

  12. Rearrange logrep worker's snapshot handling some more.

  13. doc: Update information of new messages for logical replication.

  14. ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION

  15. Allow pgoutput to send logical decoding messages.

  16. Refactor function parse_output_parameters.

  17. Avoid repeated decoding of prepared transactions after a restart.

  18. Fix an oversight in ReorderBufferFinishPrepared.

  19. Allow multiple xacts during table sync in logical replication.

  20. Fix replication of in-progress transactions in tablesync worker.

  21. Fix 'skip-empty-xacts' option in test_decoding for streaming mode.

  22. Use Enum for top level logical replication message types.

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

  24. Fix the logical streaming test.

  25. Implement streaming mode in ReorderBuffer.

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

  27. Store 2PC GID in commit/abort WAL recs for logical decoding