Horton

Re: Skipping logical replication transactions on subscriber side

Masahiko Sawada <sawada.mshk@gmail.com>

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From: Masahiko Sawada <sawada.mshk@gmail.com>
To: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>
Cc: Greg Nancarrow <gregn4422@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, "tanghy.fnst@fujitsu.com" <tanghy.fnst@fujitsu.com>, "osumi.takamichi@fujitsu.com" <osumi.takamichi@fujitsu.com>, Alexey Lesovsky <lesovsky@gmail.com>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>, vignesh C <vignesh21@gmail.com>
Date: 2021-11-24T02:20:23Z
Lists: pgsql-hackers 
On Thu, Nov 18, 2021 at 12:52 PM houzj.fnst@fujitsu.com
<houzj.fnst@fujitsu.com> wrote:
>
> On Tuesday, November 16, 2021 2:31 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> > Right. I've fixed this issue and attached an updated patch.
> >
> Hi,
>
> I have few comments for the testcases.
>
> 1)
>
> +my $appname = 'tap_sub';
> +$node_subscriber->safe_psql(
> +    'postgres',
> +    "CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION tap_pub WITH (streaming = off, two_phase = on);");
> +my $appname_streaming = 'tap_sub_streaming';
> +$node_subscriber->safe_psql(
> +    'postgres',
> +    "CREATE SUBSCRIPTION tap_sub_streaming CONNECTION '$publisher_connstr application_name=$appname_streaming' PUBLICATION tap_pub_streaming WITH (streaming = on, two_phase = on);");
> +
>
> I think we can remove the 'application_name=$appname', so that the command
> could be shorter.

But we wait for the subscription to catch up by using
wait_for_catchup() with application_name, no?

>
> 2)
> +...(streaming = on, two_phase = on);");
> Besides, is there some reasons to set two_phase to ? If so,
> It might be better to add some comments about it.
>

Yes, two_phase = on is required by the tests for skip transaction
patch. WIll remove it.

>
> 3)
> +CREATE PUBLICATION tap_pub_streaming FOR TABLE test_tab_streaming;
> +]);
> +
>
> It seems there's no tests to use the table test_tab_streaming. I guess this
> table is used to test streaming change error, maybe we can add some tests for
> it ?

Oops, similarly this is also required by the skip transaction tests.
Will remove it.

Regards,

--
Masahiko Sawada
EDB:  https://www.enterprisedb.com/

Commits

  1. Test ALIGNOF_DOUBLE==4 compatibility under ALIGNOF_DOUBLE==8.

  2. Reorder subskiplsn in pg_subscription to avoid alignment issues.

  3. Add ALTER SUBSCRIPTION ... SKIP.

  4. Optionally disable subscriptions on error.

  5. Update docs of logical replication for commit 8d74fc96db.

  6. Respect permissions within logical replication.

  7. Fix regression test failure caused by commit 8d74fc96db.

  8. Add a view to show the stats of subscription workers.

  9. Add logical change details to logical replication worker errcontext.

  10. Rename LOGICAL_REP_MSG_STREAM_END to LOGICAL_REP_MSG_STREAM_STOP.

  11. Fix typo in protocol.sgml.

  12. Remove unused argument in apply_handle_commit_internal().

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

  14. Reorder pg_sequence columns to avoid alignment issue