Fix the initial sync tables with no columns.

Amit Kapila · Amit Kapila · commit eeb0ebad79d9 · 2023-11-22T11:44:14.000+05:30
The copy command formed for initial sync was using parenthesis for tables with no columns leading to syntax error. This patch avoids adding parenthesis for such tables. Reported-by: Justin G Author: Vignesh C Reviewed-by: Peter Smith, Amit Kapila Backpatch-through: 15 Discussion: http://postgr.es/m/18203-df37fe354b626670@postgresql.org
diff --git a/src/backend/replication/logical/tablesync.c b/src/backend/replication/logical/tablesync.c
@@ -1124,22 +1124,30 @@ copy_table(Relation rel)
 	/* Regular table with no row filter */
 	if (lrel.relkind == RELKIND_RELATION && qual == NIL)
 	{
-		appendStringInfo(&cmd, "COPY %s (",
+		appendStringInfo(&cmd, "COPY %s",
 						 quote_qualified_identifier(lrel.nspname, lrel.relname));
 
-		/*
-		 * XXX Do we need to list the columns in all cases? Maybe we're
-		 * replicating all columns?
-		 */
-		for (int i = 0; i < lrel.natts; i++)
+		/* If the table has columns, then specify the columns */
+		if (lrel.natts)
 		{
-			if (i > 0)
-				appendStringInfoString(&cmd, ", ");
+			appendStringInfoString(&cmd, " (");
 
-			appendStringInfoString(&cmd, quote_identifier(lrel.attnames[i]));
+			/*
+			 * XXX Do we need to list the columns in all cases? Maybe we're
+			 * replicating all columns?
+			 */
+			for (int i = 0; i < lrel.natts; i++)
+			{
+				if (i > 0)
+					appendStringInfoString(&cmd, ", ");
+
+				appendStringInfoString(&cmd, quote_identifier(lrel.attnames[i]));
+			}
+
+			appendStringInfoString(&cmd, ")");
 		}
 
-		appendStringInfoString(&cmd, ") TO STDOUT");
+		appendStringInfoString(&cmd, " TO STDOUT");
 	}
 	else
 	{
diff --git a/src/test/subscription/t/001_rep_changes.pl b/src/test/subscription/t/001_rep_changes.pl
@@ -57,6 +57,11 @@
 	"CREATE INDEX idx_no_replidentity_index ON tab_no_replidentity_index(c1)"
 );
 
+# Replicate the changes without columns
+$node_publisher->safe_psql('postgres', "CREATE TABLE tab_no_col()");
+$node_publisher->safe_psql('postgres',
+	"INSERT INTO tab_no_col default VALUES");
+
 # Setup structure on subscriber
 $node_subscriber->safe_psql('postgres', "CREATE TABLE tab_notrep (a int)");
 $node_subscriber->safe_psql('postgres', "CREATE TABLE tab_ins (a int)");
@@ -87,13 +92,16 @@
 	"CREATE INDEX idx_no_replidentity_index ON tab_no_replidentity_index(c1)"
 );
 
+# replication of the table without columns
+$node_subscriber->safe_psql('postgres', "CREATE TABLE tab_no_col()");
+
 # Setup logical replication
 my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
 $node_publisher->safe_psql('postgres', "CREATE PUBLICATION tap_pub");
 $node_publisher->safe_psql('postgres',
 	"CREATE PUBLICATION tap_pub_ins_only WITH (publish = insert)");
 $node_publisher->safe_psql('postgres',
-	"ALTER PUBLICATION tap_pub ADD TABLE tab_rep, tab_full, tab_full2, tab_mixed, tab_include, tab_nothing, tab_full_pk, tab_no_replidentity_index"
+	"ALTER PUBLICATION tap_pub ADD TABLE tab_rep, tab_full, tab_full2, tab_mixed, tab_include, tab_nothing, tab_full_pk, tab_no_replidentity_index, tab_no_col"
 );
 $node_publisher->safe_psql('postgres',
 	"ALTER PUBLICATION tap_pub_ins_only ADD TABLE tab_ins");
@@ -141,6 +149,9 @@
 $node_publisher->safe_psql('postgres',
 	"INSERT INTO tab_no_replidentity_index VALUES(1)");
 
+$node_publisher->safe_psql('postgres',
+	"INSERT INTO tab_no_col default VALUES");
+
 $node_publisher->wait_for_catchup('tap_sub');
 
 $result = $node_subscriber->safe_psql('postgres',
@@ -169,6 +180,10 @@
 	1,
 	"value replicated to subscriber without replica identity index");
 
+$result =
+  $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM tab_no_col");
+is($result, qq(2), 'check replicated changes for table having no columns');
+
 # insert some duplicate rows
 $node_publisher->safe_psql('postgres',
 	"INSERT INTO tab_full SELECT generate_series(1,10)");
