Replicate generated columns when 'publish_generated_columns' is set.

This patch builds on the work done in commit 745217a051 by enabling the
replication of generated columns alongside regular column changes through
a new publication parameter: publish_generated_columns.

Example usage:
CREATE PUBLICATION pub1 FOR TABLE tab_gencol WITH (publish_generated_columns = true);

The column list takes precedence. If the generated columns are specified
in the column list, they will be replicated even if
'publish_generated_columns' is set to false. Conversely, if generated
columns are not included in the column list (assuming the user specifies a
column list), they will not be replicated even if
'publish_generated_columns' is true.

Author: Vignesh C, Shubham Khanna
Reviewed-by: Peter Smith, Amit Kapila, Hayato Kuroda, Shlok Kyal, Ajin Cherian, Hou Zhijie, Masahiko Sawada
Discussion: https://postgr.es/m/B80D17B2-2C8E-4C7D-87F2-E5B4BE3C069E@gmail.com

3 files changed, 26 insertions, 4 deletions

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index f02f67d7b86..898b6ddc8df 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -514,9 +514,11 @@ CREATE TABLE people (
     </listitem>
     <listitem>
      <para>
-      Generated columns can be replicated during logical replication by
-      including them in the column list of the
-      <command>CREATE PUBLICATION</command> command.
+      Generated columns are allowed to be replicated during logical replication
+      according to the <command>CREATE PUBLICATION</command> parameter
+      <link linkend="sql-createpublication-params-with-publish-generated-columns">
+      <literal>publish_generated_columns</literal></link> or by including them
+      in the column list of the <command>CREATE PUBLICATION</command> command.
      </para>
     </listitem>
    </itemizedlist>
diff --git a/doc/src/sgml/protocol.sgml b/doc/src/sgml/protocol.sgml
index 71b6b2a535f..4c0a1a00688 100644
--- a/doc/src/sgml/protocol.sgml
+++ b/doc/src/sgml/protocol.sgml
@@ -7477,7 +7477,7 @@ psql "dbname=postgres replication=database" -c "IDENTIFY_SYSTEM;"
      </variablelist>
 
      <para>
-      Next, one of the following submessages appears for each column:
+      Next, one of the following submessages appears for each published column:
 
       <variablelist>
        <varlistentry>
diff --git a/doc/src/sgml/ref/create_publication.sgml b/doc/src/sgml/ref/create_publication.sgml
index d2cac06fd76..f8e217d6610 100644
--- a/doc/src/sgml/ref/create_publication.sgml
+++ b/doc/src/sgml/ref/create_publication.sgml
@@ -189,6 +189,26 @@ CREATE PUBLICATION <replaceable class="parameter">name</replaceable>
         </listitem>
        </varlistentry>
 
+       <varlistentry id="sql-createpublication-params-with-publish-generated-columns">
+        <term><literal>publish_generated_columns</literal> (<type>boolean</type>)</term>
+        <listitem>
+         <para>
+          Specifies whether the generated columns present in the tables
+          associated with the publication should be replicated.
+          The default is <literal>false</literal>.
+         </para>
+
+         <note>
+          <para>
+           If the subscriber is from a release prior to 18, then initial table
+           synchronization won't copy generated columns even if parameter
+           <literal>publish_generated_columns</literal> is true in the
+           publisher.
+          </para>
+         </note>
+        </listitem>
+       </varlistentry>
+
        <varlistentry id="sql-createpublication-params-with-publish-via-partition-root">
         <term><literal>publish_via_partition_root</literal> (<type>boolean</type>)</term>
         <listitem>