diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index aae6adc15c..440b6aac4b 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -1552,7 +1552,10 @@ exec_replication_command(const char *cmd_string)
 				DestReceiver *dest = CreateDestReceiver(DestRemoteSimple);
 				VariableShowStmt *n = (VariableShowStmt *) cmd_node;
 
+				/* syscache access needs a transaction environment */
+				StartTransactionCommand();
 				GetPGVariable(n->name, dest);
+				CommitTransactionCommand();
 			}
 			break;
 
diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index beb45551a2..f6659d3959 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -3,11 +3,14 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 26;
+use Test::More tests => 32;
 
 # Initialize master node
 my $node_master = get_new_node('master');
-$node_master->init(allows_streaming => 1);
+# A specific role is created to perform some tests related to replication,
+# and it needs proper authentication configuration.
+$node_master->init(allows_streaming => 1,
+	auth_extra => ['--create-role', 'repl_role']);
 $node_master->start;
 my $backup_name = 'my_backup';
 
@@ -117,6 +120,55 @@ test_target_session_attrs($node_master, $node_standby_1, $node_master, "any",
 test_target_session_attrs($node_standby_1, $node_master, $node_standby_1,
 	"any", 0);
 
+# Test for SHOW commands using a WAL sender connection with a replication
+# role.
+note "testing SHOW commands for replication connection";
+
+$node_master->psql('postgres',"
+CREATE ROLE repl_role REPLICATION LOGIN;
+GRANT pg_read_all_settings TO repl_role;");
+my $master_host = $node_master->host;
+my $master_port = $node_master->port;
+my $connstr_common = "host=$master_host port=$master_port user=repl_role";
+my $connstr_rep = "$connstr_common replication=1";
+my $connstr_db = "$connstr_common replication=database dbname=postgres";
+
+# Test SHOW ALL
+my ($ret, $stdout, $stderr) =
+    $node_master->psql('postgres', 'SHOW ALL;',
+		       on_error_die => 1,
+		       extra_params => [ '-d', $connstr_rep ]);
+ok($ret == 0, "SHOW ALL with replication role and physical replication");
+($ret, $stdout, $stderr) =
+    $node_master->psql('postgres', 'SHOW ALL;',
+		       on_error_die => 1,
+		       extra_params => [ '-d', $connstr_db ]);
+ok($ret == 0, "SHOW ALL with replication role and logical replication");
+
+# Test SHOW with a user-settable parameter
+($ret, $stdout, $stderr) =
+    $node_master->psql('postgres', 'SHOW work_mem;',
+		       on_error_die => 1,
+		       extra_params => [ '-d', $connstr_rep ]);
+ok($ret == 0, "SHOW with user-settable parameter, replication role and physical replication");
+($ret, $stdout, $stderr) =
+    $node_master->psql('postgres', 'SHOW work_mem;',
+		       on_error_die => 1,
+		       extra_params => [ '-d', $connstr_db ]);
+ok($ret == 0, "SHOW with user-settable parameter, replication role and logical replication");
+
+# Test SHOW with a superuser-settable parameter
+($ret, $stdout, $stderr) =
+    $node_master->psql('postgres', 'SHOW primary_conninfo;',
+		       on_error_die => 1,
+		       extra_params => [ '-d', $connstr_rep ]);
+ok($ret == 0, "SHOW with superuser-settable parameter, replication role and physical replication");
+($ret, $stdout, $stderr) =
+    $node_master->psql('postgres', 'SHOW primary_conninfo;',
+		       on_error_die => 1,
+		       extra_params => [ '-d', $connstr_db ]);
+ok($ret == 0, "SHOW with superuser-settable parameter, replication role and logical replication");
+
 note "switching to physical replication slot";
 
 # Switch to using a physical replication slot. We can do this without a new