Fix empty deleteTimeseries requests (#18012)

Author: Caideyipi

iotdb-client/session/src/main/java/org/apache/iotdb/session/SessionConnection.java

@@ -864,6 +864,9 @@ private TSStatus insertTabletsInternal(TSInsertTabletsReq request) throws TExcep
 
   protected void deleteTimeseries(List<String> paths)
       throws IoTDBConnectionException, StatementExecutionException {
+    if (paths.isEmpty()) {
+      return;
+    }
     callWithRetryAndVerify(() -> client.deleteTimeseries(sessionId, paths));
   }
 

iotdb-client/session/src/main/java/org/apache/iotdb/session/pool/SessionPool.java

@@ -2013,6 +2013,9 @@ public void deleteTimeseries(String path)
   @Override
   public void deleteTimeseries(List<String> paths)
       throws IoTDBConnectionException, StatementExecutionException {
+    if (paths.isEmpty()) {
+      return;
+    }
     ISession session = getSession();
     try {
       session.deleteTimeseries(paths);

iotdb-client/session/src/test/java/org/apache/iotdb/session/SessionConnectionTest.java

@@ -351,6 +351,14 @@ public void testInsertRecord()
     sessionConnection.deleteTimeseries(Arrays.asList("root.sg1.d1.s1"));
   }
 
+  @Test
+  public void testDeleteEmptyTimeseries()
+      throws IoTDBConnectionException, StatementExecutionException, TException {
+    sessionConnection.deleteTimeseries(Collections.emptyList());
+
+    Mockito.verify(client, Mockito.never()).deleteTimeseries(anyLong(), any());
+  }
+
   @Test
   public void testDeleteData() throws IoTDBConnectionException, StatementExecutionException {
     sessionConnection.deleteData(new TSDeleteDataReq());

iotdb-client/session/src/test/java/org/apache/iotdb/session/pool/SessionPoolTest.java

@@ -777,6 +777,17 @@ public void testDeleteTimeseriesList()
         ((ConcurrentLinkedDeque<ISession>) Whitebox.getInternalState(sessionPool, "queue")).size());
   }
 
+  @Test
+  public void testDeleteEmptyTimeseriesList()
+      throws IoTDBConnectionException, StatementExecutionException {
+    sessionPool.deleteTimeseries(Collections.emptyList());
+
+    Mockito.verify(session, Mockito.never()).deleteTimeseries(Mockito.<List<String>>any());
+    assertEquals(
+        1,
+        ((ConcurrentLinkedDeque<ISession>) Whitebox.getInternalState(sessionPool, "queue")).size());
+  }
+
   @Test
   public void testDeleteData() throws IoTDBConnectionException, StatementExecutionException {
     String path = "root.device1.temperature";

iotdb-core/datanode/src/main/java/org/apache/iotdb/db/protocol/thrift/impl/ClientRPCServiceImpl.java

@@ -2026,6 +2026,9 @@ public TSStatus deleteTimeseries(long sessionId, List<String> path) {
         return getNotLoggedInStatus();
       }
 
+      if (path.isEmpty()) {
+        return RpcUtils.getStatus(TSStatusCode.SUCCESS_STATUS);
+      }
       // Step 1: transfer from DeleteStorageGroupsReq to Statement
       DeleteTimeSeriesStatement statement =
           StatementGenerator.createDeleteTimeSeriesStatement(path);