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;