Horton

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

Ajin Cherian <itsajin@gmail.com>

View thread View on postgr.es
From: Ajin Cherian <itsajin@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Dilip Kumar <dilipbalaut@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Masahiko Sawada <sawada.mshk@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2020-09-28T09:01:35Z
Lists: pgsql-hackers 
On Mon, Sep 28, 2020 at 6:36 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Mon, Sep 28, 2020 at 1:13 PM Ajin Cherian <itsajin@gmail.com> wrote:
> >
> > On Wed, Sep 23, 2020 at 2:39 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > I have added a new patch for supporting 2 phase commit semantics in
> > the streaming APIs for the logical decoding plugins. I have added 3
> > APIs
> > 1. stream_prepare
> > 2. stream_commit_prepared
> > 3. stream_abort_prepared
> >
> > I have also added the support for the new APIs in test_decoding
> > plugin. I have not yet added it to pgoutpout.
> >
> > I have also added a fix for the error I saw while calling
> > ReorderBufferCleanupTXN as part of FinishPrepared handling. As a
> > result I have removed the function I added earlier,
> > ReorderBufferCleanupPreparedTXN.
> >
>
> Can you explain what was the problem and how you fixed it?

When I added the changes for cleaning up tuplecids in
ReorderBufferTruncateTXN, I was not deleting it from the list
(dlist_delete), only calling  ReorderBufferReturnChange to free
memory. This logic was copied from ReorderBufferCleanupTXN, there the
lists were all cleaned up in the end, so was not present in each list
cleanup logic.

>
> > Please have a look at the new changes and let me know what you think.
> >
> > I will continue to look at:
> >
> > 1. Remove snapshots on prepare truncate.
> > 2. Bug seen while abort of prepared transaction, the prepared flag is
> > lost, and not able to make out that it was a previously prepared
> > transaction.
> >
>
> And the support of new APIs in pgoutput, right?

Yes, that also.

regards,
Ajin Cherian
Fujitsu Australia

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