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

tanghy.fnst@fujitsu.com <tanghy.fnst@fujitsu.com>

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From: "tanghy.fnst@fujitsu.com" <tanghy.fnst@fujitsu.com>
To: Peter Smith <smithpb2250@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, vignesh C <vignesh21@gmail.com>, Ajin Cherian <itsajin@gmail.com>, Greg Nancarrow <gregn4422@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2021-07-30T08:25:37Z
Lists: pgsql-hackers 
On Friday, July 30, 2021 12:02 PM Peter Smith <smithpb2250@gmail.com>wrote:
> 
> Please find attached the latest patch set v100*
> 
> v99-0002 --> v100-0001
> 

Thanks for your patch. A few comments on the test file:

1. src/test/subscription/t/022_twophase_cascade.pl

1.1
I saw your test cases for "PREPARE / COMMIT PREPARED" and "PREPARE with a nested ROLLBACK TO SAVEPOINT", but didn't see cases for "PREPARE / ROLLBACK PREPARED". Is it needless or just missing?

1.2
+# check inserts are visible at subscriber(s).
+# All the streamed data (prior to the SAVEPOINT) should be rolled back.
+# (3, 'foobar') should be committed.

I think it should be (9999, 'foobar') here.

1.3
+$result = $node_B->safe_psql('postgres', "SELECT count(*) FROM test_tab where b = 'foobar';");
+is($result, qq(1), 'Rows committed are present on subscriber B');
+$result = $node_B->safe_psql('postgres', "SELECT count(*) FROM test_tab;");
+

It seems the test is not finished yet. We didn't check the value of 'result'. Besides, maybe we should also check node_C, right?

1.4
+$node_B->append_conf('postgresql.conf',	qq(max_prepared_transactions = 10));
+$node_B->append_conf('postgresql.conf', qq(logical_decoding_work_mem = 64kB));

You see, the first line uses a TAB but the second line uses a space.
Also, we could use only one statement to append these two settings to run tests a bit faster. Thoughts?
Something like:

$node_B->append_conf(
	'postgresql.conf', qq(
	max_prepared_transactions = 10
	logical_decoding_work_mem = 64kB
));

Regards
Tang

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