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: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>
Cc: Peter Smith <smithpb2250@gmail.com>, Ajin Cherian <itsajin@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2021-03-25T11:02:31Z
Lists: pgsql-hackers 
On Wed, Mar 24, 2021 at 3:59 PM houzj.fnst@fujitsu.com
<houzj.fnst@fujitsu.com> wrote:
>
> > I have incorporated all your changes and additionally made few more changes
> > (a) got rid of LogicalRepBeginPrepareData and instead used
> > LogicalRepPreparedTxnData, (b) made a number of changes in comments and
> > docs, (c) ran pgindent, (d) modified tests to use standard wait_for_catch
> > function and removed few tests to reduce the time and to keep regression
> > tests reliable.
>
> Hi,
>
> When reading the code, I found some comments related to the patch here.
>
>                                  * XXX Now, this can even lead to a deadlock if the prepare
>                                  * transaction is waiting to get it logically replicated for
>                                  * distributed 2PC. Currently, we don't have an in-core
>                                  * implementation of prepares for distributed 2PC but some
>                                  * out-of-core logical replication solution can have such an
>                                  * implementation. They need to inform users to not have locks
>                                  * on catalog tables in such transactions.
>                                  */
>
> Since we will have in-core implementation of prepares, should we update the comments here ?
>

Fixed this in the latest patch posted by me. I have additionally
updated the docs to reflect the same.

-- 
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