Horton

Re: Skipping logical replication transactions on subscriber side

Greg Nancarrow <gregn4422@gmail.com>

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From: Greg Nancarrow <gregn4422@gmail.com>
To: Masahiko Sawada <sawada.mshk@gmail.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.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>
Date: 2021-10-12T10:58:44Z
Lists: pgsql-hackers 
On Tue, Oct 12, 2021 at 4:00 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
>
> I've attached updated patches.
>

Some comments for the v16-0003 patch:

(1) doc/src/sgml/logical-replication.sgml

The output from "SELECT * FROM pg_stat_subscription_errors;" still
shows "last_failed_time" instead of "last_error_time".

doc/src/sgml/ref/alter_subscription.sgml
(2)

Suggested update (and fix typo: restrited -> restricted):

BEFORE:
+          Setting and resetting of <literal>skip_xid</literal> option is
+          restrited to superusers.
AFTER:
+          The setting and resetting of the
<literal>skip_xid</literal> option is
+          restricted to superusers.

(3)
Suggested improvement to the wording:

BEFORE:
+          incoming change or by skipping the whole transaction.  This option
+          specifies transaction ID that logical replication worker skips to
+          apply.  The logical replication worker skips all data modification
AFTER:
+          incoming changes or by skipping the whole transaction.  This option
+          specifies the ID of the transaction whose application is to
be skipped
+          by the logical replication worker. The logical replication worker
+          skips all data modification

(4) src/backend/replication/logical/worker.c

Suggested improvement to the comment wording:

BEFORE:
+ * Stop the skipping transaction if enabled. Otherwise, commit the changes
AFTER:
+ * Stop skipping the transaction changes, if enabled. Otherwise,
commit the changes


(5) skip_xid value validation

The validation of the specified skip_xid XID value isn't great.
For example, the following value are accepted:

    ALTER SUBSCRIPTION sub SET (skip_xid='123abcz');
    ALTER SUBSCRIPTION sub SET (skip_xid='99$@*');


Regards,
Greg Nancarrow
Fujitsu Australia

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