[IOTDB-2362] [REST API] Use noQuery to execute "count", return "SHOW is not supported" (#4933)

server/src/main/java/org/apache/iotdb/db/qp/executor/PlanExecutor.java

@@ -395,7 +395,7 @@ public class PlanExecutor implements IPlanExecutor {
         return processShowQueryResource();
       default:
         throw new UnsupportedOperationException(
-            String.format("operation %s is not supported", plan.getOperatorType()));
+            String.format("operation %s is not supported", plan.getOperatorName()));
     }
   }
 

server/src/main/java/org/apache/iotdb/db/qp/physical/PhysicalPlan.java

@@ -140,6 +140,10 @@ public abstract class PhysicalPlan {
     return operatorType;
   }
 
+  public String getOperatorName() {
+    return operatorType.toString();
+  }
+
   public void setOperatorType(Operator.OperatorType operatorType) {
     this.operatorType = operatorType;
   }

server/src/main/java/org/apache/iotdb/db/qp/physical/sys/ShowPlan.java

@@ -98,6 +98,11 @@ public class ShowPlan extends PhysicalPlan {
     return String.format("%s %s", getOperatorType(), showContentType);
   }
 
+  @Override
+  public String getOperatorName() {
+    return String.format("%s: %s", getOperatorType(), showContentType);
+  }
+
   public enum ShowContentType {
     FLUSH_TASK_INFO,
     TTL,