Horton

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

Ajin Cherian <itsajin@gmail.com>

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From: Ajin Cherian <itsajin@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Masahiko Sawada <sawada.mshk@gmail.com>, Peter Smith <smithpb2250@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2021-01-05T08:40:57Z
Lists: pgsql-hackers

Attachments

On Tue, Jan 5, 2021 at 5:19 PM Amit Kapila <amit.kapila16@gmail.com> wrote:

>
> I have reviewed this test case patch and have the below comments:
>
> 1.
> +step "s1checkpoint" { CHECKPOINT; }
> ...
> +step "s2alter" { ALTER TABLE do_write ADD COLUMN addedbys2 int; }
>
> I don't see the need for the above steps and we should be able to
> generate the required scenario without these as well. Is there any
> reason to keep those?

Removed.
>
> 2.
> "s3c""s1insert"
>
> space is missing between these two.

Updated.

>
> 3.
> +# Force building of a consistent snapshot between a PREPARE and
> COMMIT PREPARED.
> +# Ensure that the whole transaction is decoded fresh at the time of
> COMMIT PREPARED.
> +permutation "s2b" "s2txid" "s1init" "s3b" "s3txid" "s2alter" "s2c"
> "s2b" "s2insert" "s2prepare" "s3c""s1insert" "s1checkpoint" "s1start"
> "s2commit" "s1start"
>
> I think we can update the above comments to indicate how and which
> important steps help us to realize the required scenario. See
> subxact_without_top.spec for reference.

Added more comments to explain the state change of logical decoding.

> 4.
> +step "s2c" { COMMIT; }
> ...
> +step "s2prepare" { PREPARE TRANSACTION 'test1'; }
> +step "s2commit" { COMMIT PREPARED 'test1'; }
>
> s2c and s2commit seem to be confusing names as both sounds like doing
> the same thing. How about changing s2commit to s2cp and s2prepare to
> s2p?

Updated.

I've addressed the above comments and the patch is attached. I've
called it v36-0007.

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