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help / color / mirror / Atom feedFrom: vignesh C <[email protected]>
To: Peter Smith <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Subject: Re: Include sequences in publications created by pg_createsubscriber
Date: Thu, 25 Jun 2026 15:30:20 +0530
Message-ID: <CALDaNm39kG3iweFqyS0=3UNOSzZn_13Cq5iEKqcyG7apXGPJbw@mail.gmail.com> (raw)
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On Thu, 25 Jun 2026 at 06:29, Peter Smith <[email protected]> wrote:
>
> Hi Vignesh.
>
> Some comments for v2.
>
> ======
> doc/src/sgml/ref/pg_createsubscriber.sgml
>
> 1.
> fresh logical replication setup. The main difference between the logical
> replication setup and <application>pg_createsubscriber</application> is how
> the data synchronization is done.
> <application>pg_createsubscriber</application>
> - does not copy the initial table data. It does only the
> synchronization phase,
> - which ensures each table is brought up to a synchronized state.
> + does not copy the initial table or sequence data. It does only the
> + synchronization phase, which ensures each table and sequence is brought up
> + to a synchronized state.
>
> 1a.
> OK. Thanks for the explanation on what was meant. Personally, I found
> the wording "sequence is brought up to a synchronized state"
> ambiguous, because in my mind the sequence value is a part of the
> sequence state.
>
> Below is some alternate wording for consideration:
>
> SUGGESTION:
> pg_createsubscriber performs only the synchronization phase, which
> prepares each table and sequence for replication. It does not copy
> table data or synchronize sequence values from the publisher.
I have separated the table and sequence part to avoid confusion.
> ~~~
>
> 1b.
> While reviewing this patch I also referred to section "29.7.
> Replicating Sequences #". [1] for more information. But there I was
> tricked by some (misleading?) wording.
> I have created another thread [2] to discuss/patch that. Please see it
> and post your thoughts.
Thanks for working on this, I have shared a couple of comments at [1].
> ~~~
>
> 2.
> + <para>
> + Note that although the publication includes sequences, sequence value
> + changes made on the publisher after reaching consistent point are not
> + synchronized incrementally. To synchronize sequence values, run
> + <link linkend="sql-altersubscription-params-refresh-sequences">
> + <command>ALTER SUBSCRIPTION ... REFRESH SEQUENCES</command></link>, which
> + fetches the current sequence state from the publisher and advances the
> + corresponding subscriber sequences.
> </para>
>
> I wonder if the last sentence is overly descriptive. Isn't it enough
> to just say:
> To synchronize sequence values, run <link
> linkend="sql-altersubscription-params-refresh-sequences"><command>ALTER
> SUBSCRIPTION ... REFRESH SEQUENCES</command></link>.
Modified
> ~~~
>
> 3.
> <para>
> Enable the subscription for each specified database on the target server.
> The subscription starts applying transactions from the replication start
> - point.
> + point. The subscription is configured to include sequences.
> </para>
>
> This implies there was some special subscription "configuration" for
> getting sequences, but it just gets sequences because sequences were
> published. Maybe you don't need to say anything here. Or, maybe reword
> to just say "The subscription will include sequences".
I have removed it from here and clarified this in step-3.
The attached v3 version patch has the changes for the same.
[1] - https://www.postgresql.org/message-id/CALDaNm1xY_Js5-jppiBzGq2HMqzCHk%2BLLpupfWp_cFcG%3DvJXmg%40mail...
Regards,
Vignesh
Attachments:
[application/octet-stream] v3-0001-Include-sequences-in-publications-created-by-pg_c.patch (7.9K, ../CALDaNm39kG3iweFqyS0=3UNOSzZn_13Cq5iEKqcyG7apXGPJbw@mail.gmail.com/2-v3-0001-Include-sequences-in-publications-created-by-pg_c.patch)
download | inline diff:
From 7f939667057e3d62ee98e08480493465691b51e1 Mon Sep 17 00:00:00 2001
From: Vignesh C <[email protected]>
Date: Fri, 19 Jun 2026 19:14:27 +0530
Subject: [PATCH v3] Include sequences in publications created by
pg_createsubscriber
pg_createsubscriber creates a publication on the publisher to establish
logical replication between the original primary and the converted
subscriber. Currently, the publication is created with FOR ALL TABLES,
which ensures that table data changes are replicated during the upgrade
process.
However, sequence state is not replicated as part of this workflow.
Recent additions to logical replication introduced support for publishing
all sequences and synchronizing sequence state through subscription
refresh. By creating publications with FOR ALL TABLES, ALL SEQUENCES,
pg_createsubscriber can take advantage of these capabilities and allow
sequence state to be synchronized before the upgraded node is promoted.
This change modifies pg_createsubscriber to include ALL SEQUENCES in the
publication it creates. Administrators can then run ALTER SUBSCRIPTION
... REFRESH SEQUENCES after the upgrade to synchronize sequence state,
ensuring a more complete and reliable upgrade workflow.
---
doc/src/sgml/ref/pg_createsubscriber.sgml | 43 +++++++++++++------
src/bin/pg_basebackup/pg_createsubscriber.c | 4 +-
.../t/040_pg_createsubscriber.pl | 8 ++++
3 files changed, 39 insertions(+), 16 deletions(-)
diff --git a/doc/src/sgml/ref/pg_createsubscriber.sgml b/doc/src/sgml/ref/pg_createsubscriber.sgml
index 3b3038d1891..eddac27af9f 100644
--- a/doc/src/sgml/ref/pg_createsubscriber.sgml
+++ b/doc/src/sgml/ref/pg_createsubscriber.sgml
@@ -49,10 +49,12 @@ PostgreSQL documentation
<para>
<application>pg_createsubscriber</application> creates a new logical
replica from a physical standby server. All tables in the specified
- database are included in the <link linkend="logical-replication">logical
- replication</link> setup. A pair of
- publication and subscription objects are created for each database. It
- must be run at the target server.
+ database are included in the
+ <link linkend="logical-replication">logical replication</link> setup. The
+ publications created by <application>pg_createsubscriber</application> also
+ include all sequences, allowing their state to be synchronized after the
+ upgrade. A pair of publication and subscription objects are created for each
+ database. It must be run at the target server.
</para>
<para>
@@ -61,7 +63,9 @@ PostgreSQL documentation
replication setup and <application>pg_createsubscriber</application> is how
the data synchronization is done. <application>pg_createsubscriber</application>
does not copy the initial table data. It does only the synchronization phase,
- which ensures each table is brought up to a synchronized state.
+ which ensures each table is brought up to a synchronized state. The
+ subscriptions are configured to include sequences, but sequence values are
+ not synchronized automatically.
</para>
<para>
@@ -75,7 +79,12 @@ PostgreSQL documentation
synchronization. For details, see the <command>CREATE SUBSCRIPTION</command>
<link linkend="sql-createsubscription-params-with-copy-data">
<literal>copy_data</literal></link> option.
+ </para>
+ <para>
+ To synchronize sequence values, run
+ <link linkend="sql-altersubscription-params-refresh-sequences">
+ <command>ALTER SUBSCRIPTION ... REFRESH SEQUENCES</command></link>.
</para>
</refsect1>
@@ -275,10 +284,10 @@ PostgreSQL documentation
<listitem>
<para>
<literal>publications</literal>:
- The <literal>FOR ALL TABLES</literal> publications established for this
- subscriber are always dropped; specifying this object type causes all
- other publications replicated from the source server to be dropped as
- well.
+ The <literal>FOR ALL TABLES, ALL SEQUENCES</literal> publications
+ established for this subscriber are always dropped; specifying this
+ object type causes all other publications replicated from the source
+ server to be dropped as well.
</para>
</listitem>
</itemizedlist>
@@ -323,7 +332,8 @@ PostgreSQL documentation
If a specified publication already exists on the publisher, it is reused.
It is useful to partially replicate the database if the specified
publication includes a list of tables. If the publication does not exist,
- it is automatically created with <literal>FOR ALL TABLES</literal>. Use
+ it is automatically created with
+ <literal>FOR ALL TABLES, ALL SEQUENCES</literal>. Use
<option>--dry-run</option> option to preview which publications will be
reused and which will be created.
</para>
@@ -532,10 +542,15 @@ PostgreSQL documentation
<step>
<para>
Create a publication and replication slot for each specified database on
- the source server. Each publication is created using <link
- linkend="sql-createpublication-params-for-all-tables"><literal>FOR ALL
- TABLES</literal></link>. If the <option>--publication</option> option
- is not specified, the publication has the following name pattern:
+ the source server. If the --publication option is not specified,
+ <application>pg_createsubscriber</application> creates a publication
+ using <link linkend="sql-createpublication-params-for-all-tables">
+ <literal>FOR ALL TABLES</literal></link> and
+ <link linkend="sql-createpublication-params-for-all-sequences">
+ <literal>ALL SEQUENCES</literal></link>. Otherwise, it uses the
+ user-specified publication, which includes the objects defined by that
+ publication. If the <option>--publication</option> option is not
+ specified, the publication has the following name pattern:
<quote><literal>pg_createsubscriber_%u_%x</literal></quote> (parameter:
database <parameter>oid</parameter>, random <parameter>int</parameter>).
If the <option>--replication-slot</option> option is not specified, the
diff --git a/src/bin/pg_basebackup/pg_createsubscriber.c b/src/bin/pg_basebackup/pg_createsubscriber.c
index 4d705778454..ec18faf50eb 100644
--- a/src/bin/pg_basebackup/pg_createsubscriber.c
+++ b/src/bin/pg_basebackup/pg_createsubscriber.c
@@ -1788,7 +1788,7 @@ wait_for_end_recovery(const char *conninfo, const struct CreateSubscriberOptions
}
/*
- * Create a publication that includes all tables in the database.
+ * Create a publication that includes all tables and sequences in the database.
*/
static void
create_publication(PGconn *conn, struct LogicalRepInfo *dbinfo)
@@ -1840,7 +1840,7 @@ create_publication(PGconn *conn, struct LogicalRepInfo *dbinfo)
pg_log_info("creating publication \"%s\" in database \"%s\"",
dbinfo->pubname, dbinfo->dbname);
- appendPQExpBuffer(str, "CREATE PUBLICATION %s FOR ALL TABLES",
+ appendPQExpBuffer(str, "CREATE PUBLICATION %s FOR ALL TABLES, ALL SEQUENCES",
ipubname_esc);
pg_log_debug("command is: %s", str->data);
diff --git a/src/bin/pg_basebackup/t/040_pg_createsubscriber.pl b/src/bin/pg_basebackup/t/040_pg_createsubscriber.pl
index 9252d1c3c5c..044f202cb35 100644
--- a/src/bin/pg_basebackup/t/040_pg_createsubscriber.pl
+++ b/src/bin/pg_basebackup/t/040_pg_createsubscriber.pl
@@ -503,6 +503,14 @@ is($result, qq(0),
'the physical replication slot used as primary_slot_name has been removed'
);
+# Verify that the publication is configured to publish all tables and
+# all sequences.
+$result = $node_p->safe_psql($db2,
+ "SELECT puballtables, puballsequences FROM pg_publication");
+is( $result, qq(t|t),
+ "publication is created with both all-tables and all-sequences enabled"
+);
+
# Insert rows on P
$node_p->safe_psql($db1, "INSERT INTO tbl1 VALUES('third row')");
$node_p->safe_psql($db2, "INSERT INTO tbl2 VALUES('row 1')");
--
2.53.0
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Subject: Re: Include sequences in publications created by pg_createsubscriber
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