Horton

Re: Logical Replication of sequences

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>
Cc: Dilip Kumar <dilipbalaut@gmail.com>, "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, vignesh C <vignesh21@gmail.com>, Peter Smith <smithpb2250@gmail.com>, shveta malik <shveta.malik@gmail.com>, Shlok Kyal <shlok.kyal.oss@gmail.com>, Chao Li <li.evan.chao@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, Nisha Moond <nisha.moond412@gmail.com>, Peter Eisentraut <peter@eisentraut.org>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Euler Taveira <euler@eulerto.com>, Michael Paquier <michael@paquier.xyz>, "Jonathan S. Katz" <jkatz@postgresql.org>
Date: 2025-10-17T08:50:21Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Doc: Add documentation for sequence synchronization.

  2. Remove unused assignment in CREATE PUBLICATION grammar.

  3. Add seq_sync_error_count to subscription statistics.

  4. Fix few issues in commit 5509055d69.

  5. Add sequence synchronization for logical replication.

  6. Add worker type argument to logical replication worker functions.

  7. Introduce "REFRESH SEQUENCES" for subscriptions.

  8. Refactor logical worker synchronization code into a separate file.

  9. Standardize use of REFRESH PUBLICATION in code and messages.

  10. Add "ALL SEQUENCES" support to publications.

  11. Expose sequence page LSN via pg_get_sequence_data.

  12. Resume conflict-relevant data retention automatically.

  13. Post-commit review fixes for 228c370868.

  14. Generate GUC tables from .dat file

On Thu, Oct 16, 2025 at 4:53 PM Zhijie Hou (Fujitsu)
<houzj.fnst@fujitsu.com> wrote:
>
> Thanks! Here is the remaining patches, which addressed all pending comments.
>

Few comments on 0001/0003:
========================
1.
@@ -480,7 +480,9 @@ RemoveSubscriptionRel(Oid subid, Oid relid)
  * leave tablesync slots or origins in the system when the
  * corresponding table is dropped.
  */
- if (!OidIsValid(subid) && subrel->srsubstate != SUBREL_STATE_READY)
+ if (!OidIsValid(subid) &&
+ get_rel_relkind(subrel->srrelid) != RELKIND_SEQUENCE &&
+ subrel->srsubstate != SUBREL_STATE_READY)
  {

Here, why don't we allow sequence rel to be removed? Please add some comments.

2.
/*
  * Get the relations for the subscription.
  *
- * If not_ready is true, return only the relations that are not in a ready
- * state, otherwise return all the relations of the subscription.  The
- * returned list is palloc'ed in the current memory context.
+ * get_tables: get relations for tables of the subscription.
+ *
+ * get_sequences: get relations for sequences of the subscription.
+ *
+ * not_ready:
+ * If getting tables and not_ready is false, retrieve all tables;
+ * otherwise, retrieve only tables that have not reached the READY state.
+ * If getting sequences and not_ready is false, retrieve all sequences;
+ * otherwise, retrieve only sequences that have not reached the READY state.
+ *
+ * The returned list is palloc'ed in the current memory context.
  */
 List *
-GetSubscriptionRelations(Oid subid, bool not_ready)
+GetSubscriptionRelations(Oid subid, bool get_tables, bool get_sequences,
+ bool not_ready)

The existing code comments (without the patch) are good enough for this change.

3. Move catalogs.sgml, alter_subscription.sgml (parts related to 0001)
from 0003 to 0001. Also, see if anything else can be moved.

4.
      <para>
-      Fetch missing table information from publisher.  This will start
+      Fetch missing table information from the publisher.  This will start
       replication of tables that were added to the subscribed-to publications
       since <link linkend="sql-createsubscription">
       <command>CREATE SUBSCRIPTION</command></link> or
       the last invocation of <command>REFRESH PUBLICATION</command>.
      </para>

+     <para>
+      Also, fetch missing sequence information from the publisher.
+     </para>

The second para should be merged into the first one: Fetch missing
table and sequence information from the publisher.

5.
+      </para>
+      <para>
+       State codes for sequences:
+       <literal>i</literal> = initialize,
+       <literal>d</literal> = re-synchronize,
+       <literal>r</literal> = ready
</para></entry>

I think we need to remove the 'd' state from here as the patch 0001
changes always update the sequence state to init.

-- 
With Regards,
Amit Kapila.