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Posted to commits@iotdb.apache.org by xi...@apache.org on 2022/03/14 05:53:40 UTC
[iotdb] 08/11: design of source, sink and internal operators
This is an automated email from the ASF dual-hosted git repository.
xingtanzjr pushed a commit to branch xingtanzjr/mpp-query-basis
in repository https://gitbox.apache.org/repos/asf/iotdb.git
commit d32aa168d108eaa4fd6a6784eaab92b97f8408b3
Author: Steve Yurong Su <ro...@apache.org>
AuthorDate: Tue Mar 8 23:40:05 2022 +0800
design of source, sink and internal operators
---
.../distribution/operator/ExecutableOperator.java | 34 ++++++++++++++++++
.../operator/internal/DeviceMergeOperator.java | 2 +-
.../operator/internal/FillOperator.java | 2 +-
.../operator/internal/FilterInternalOperator.java | 2 +-
.../operator/internal/GroupByLevelOperator.java | 2 +-
.../operator/internal/InternalOperator.java | 20 +++--------
.../operator/internal/LimitOperator.java | 2 +-
.../operator/internal/OffsetOperator.java | 2 +-
.../operator/internal/SeriesAggregateOperator.java | 2 +-
.../operator/internal/SortOperator.java | 2 +-
.../operator/internal/TimeJoinOperator.java | 2 +-
.../operator/internal/WithoutOperator.java | 2 +-
.../operator/sink/CsvSinkOperator.java | 41 ++++++++++++++++++++++
.../operator/sink/RestSinkOperator.java | 41 ++++++++++++++++++++++
.../distribution/operator/sink/SinkOperator.java | 28 +++++++++++++++
.../operator/sink/ThriftSinkOperator.java | 41 ++++++++++++++++++++++
.../operator/source/CsvSourceOperator.java | 41 ++++++++++++++++++++++
.../operator/source/SeriesScanOperator.java | 10 ++++--
.../operator/source/SourceOperator.java | 28 +++++++++++++++
19 files changed, 277 insertions(+), 27 deletions(-)
diff --git a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/ExecutableOperator.java b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/ExecutableOperator.java
new file mode 100644
index 0000000..00a7a6a
--- /dev/null
+++ b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/ExecutableOperator.java
@@ -0,0 +1,34 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.iotdb.cluster.query.distribution.operator;
+
+import org.apache.iotdb.cluster.query.distribution.common.TreeNode;
+
+public abstract class ExecutableOperator<T> extends TreeNode<ExecutableOperator<?>> {
+
+ // Resource control, runtime control...
+
+ // Judge whether current operator has more result
+ public abstract boolean hasNext();
+
+ // Get next result batch of this operator
+ // Return null if there is no more result to return
+ public abstract T getNextBatch();
+}
diff --git a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/DeviceMergeOperator.java b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/DeviceMergeOperator.java
index b912994..d4bbced 100644
--- a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/DeviceMergeOperator.java
+++ b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/DeviceMergeOperator.java
@@ -1,4 +1,4 @@
-package org.apache.iotdb.cluster.query.distribution.operator;
+package org.apache.iotdb.cluster.query.distribution.operator.internal;
import org.apache.iotdb.cluster.query.distribution.common.Tablet;
import org.apache.iotdb.cluster.query.distribution.common.TraversalOrder;
diff --git a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/FillOperator.java b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/FillOperator.java
index 8ee610a..595a27e 100644
--- a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/FillOperator.java
+++ b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/FillOperator.java
@@ -1,4 +1,4 @@
-package org.apache.iotdb.cluster.query.distribution.operator;
+package org.apache.iotdb.cluster.query.distribution.operator.internal;
import org.apache.iotdb.cluster.query.distribution.common.FillPolicy;
import org.apache.iotdb.cluster.query.distribution.common.Tablet;
diff --git a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/FilterInternalOperator.java b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/FilterInternalOperator.java
index ecbda0f..f41d768 100644
--- a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/FilterInternalOperator.java
+++ b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/FilterInternalOperator.java
@@ -1,4 +1,4 @@
-package org.apache.iotdb.cluster.query.distribution.operator;
+package org.apache.iotdb.cluster.query.distribution.operator.internal;
import org.apache.iotdb.cluster.query.distribution.common.Tablet;
import org.apache.iotdb.db.qp.logical.crud.FilterOperator;
diff --git a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/GroupByLevelOperator.java b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/GroupByLevelOperator.java
index c6e00d2..9cab1c0 100644
--- a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/GroupByLevelOperator.java
+++ b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/GroupByLevelOperator.java
@@ -1,4 +1,4 @@
-package org.apache.iotdb.cluster.query.distribution.operator;
+package org.apache.iotdb.cluster.query.distribution.operator.internal;
import org.apache.iotdb.cluster.query.distribution.common.GroupByTimeParameter;
import org.apache.iotdb.cluster.query.distribution.common.LevelBucketInfo;
diff --git a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/InternalOperator.java b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/InternalOperator.java
index 0692381..a5b8b5b 100644
--- a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/InternalOperator.java
+++ b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/InternalOperator.java
@@ -1,17 +1,7 @@
-package org.apache.iotdb.cluster.query.distribution.operator;
+package org.apache.iotdb.cluster.query.distribution.operator.internal;
-import org.apache.iotdb.cluster.query.distribution.common.TreeNode;
+import org.apache.iotdb.cluster.query.distribution.operator.ExecutableOperator;
-/**
- * @author xingtanzjr The base class of query executable operators, which is used to compose logical
- * query plan. TODO: consider how to restrict the children type for each type of ExecOperator
- */
-public abstract class InternalOperator<T> extends TreeNode<InternalOperator<?>> {
-
- // Judge whether current operator has more result
- public abstract boolean hasNext();
-
- // Get next result batch of this operator
- // Return null if there is no more result to return
- public abstract T getNextBatch();
-}
+// 从 buffer 拉数据
+// 推送到下游的逻辑
+public abstract class InternalOperator<T> extends ExecutableOperator<T> {}
diff --git a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/LimitOperator.java b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/LimitOperator.java
index 9075f64..1330eee 100644
--- a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/LimitOperator.java
+++ b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/LimitOperator.java
@@ -1,4 +1,4 @@
-package org.apache.iotdb.cluster.query.distribution.operator;
+package org.apache.iotdb.cluster.query.distribution.operator.internal;
import org.apache.iotdb.cluster.query.distribution.common.Tablet;
diff --git a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/OffsetOperator.java b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/OffsetOperator.java
index c6f79ac..aa82d8c 100644
--- a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/OffsetOperator.java
+++ b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/OffsetOperator.java
@@ -1,4 +1,4 @@
-package org.apache.iotdb.cluster.query.distribution.operator;
+package org.apache.iotdb.cluster.query.distribution.operator.internal;
import org.apache.iotdb.cluster.query.distribution.common.Tablet;
diff --git a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/SeriesAggregateOperator.java b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/SeriesAggregateOperator.java
index 96a5c86..889c50b 100644
--- a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/SeriesAggregateOperator.java
+++ b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/SeriesAggregateOperator.java
@@ -1,4 +1,4 @@
-package org.apache.iotdb.cluster.query.distribution.operator;
+package org.apache.iotdb.cluster.query.distribution.operator.internal;
import org.apache.iotdb.cluster.query.distribution.common.GroupByTimeParameter;
import org.apache.iotdb.cluster.query.distribution.common.SeriesBatchAggInfo;
diff --git a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/SortOperator.java b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/SortOperator.java
index fa83be7..d2aee44 100644
--- a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/SortOperator.java
+++ b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/SortOperator.java
@@ -1,4 +1,4 @@
-package org.apache.iotdb.cluster.query.distribution.operator;
+package org.apache.iotdb.cluster.query.distribution.operator.internal;
import org.apache.iotdb.cluster.query.distribution.common.Tablet;
import org.apache.iotdb.cluster.query.distribution.common.TraversalOrder;
diff --git a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/TimeJoinOperator.java b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/TimeJoinOperator.java
index c4ae6f3..bd7cf37 100644
--- a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/TimeJoinOperator.java
+++ b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/TimeJoinOperator.java
@@ -1,4 +1,4 @@
-package org.apache.iotdb.cluster.query.distribution.operator;
+package org.apache.iotdb.cluster.query.distribution.operator.internal;
import org.apache.iotdb.cluster.query.distribution.common.Tablet;
import org.apache.iotdb.cluster.query.distribution.common.TraversalOrder;
diff --git a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/WithoutOperator.java b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/WithoutOperator.java
index 535a3d6..f678a2c 100644
--- a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/WithoutOperator.java
+++ b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/internal/WithoutOperator.java
@@ -1,4 +1,4 @@
-package org.apache.iotdb.cluster.query.distribution.operator;
+package org.apache.iotdb.cluster.query.distribution.operator.internal;
import org.apache.iotdb.cluster.query.distribution.common.Tablet;
import org.apache.iotdb.cluster.query.distribution.common.WithoutPolicy;
diff --git a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/sink/CsvSinkOperator.java b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/sink/CsvSinkOperator.java
new file mode 100644
index 0000000..17bba65
--- /dev/null
+++ b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/sink/CsvSinkOperator.java
@@ -0,0 +1,41 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.iotdb.cluster.query.distribution.operator.sink;
+
+import org.apache.iotdb.cluster.query.distribution.common.SeriesBatchData;
+
+public class CsvSinkOperator extends SinkOperator<SeriesBatchData> {
+
+ @Override
+ public void close() throws Exception {}
+
+ @Override
+ public boolean hasNext() {
+ return false;
+ }
+
+ @Override
+ public SeriesBatchData getNextBatch() {
+ return null;
+ }
+
+ @Override
+ public void open() throws Exception {}
+}
diff --git a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/sink/RestSinkOperator.java b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/sink/RestSinkOperator.java
new file mode 100644
index 0000000..d8e6588
--- /dev/null
+++ b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/sink/RestSinkOperator.java
@@ -0,0 +1,41 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.iotdb.cluster.query.distribution.operator.sink;
+
+import org.apache.iotdb.cluster.query.distribution.common.SeriesBatchData;
+
+public class RestSinkOperator extends SinkOperator<SeriesBatchData> {
+
+ @Override
+ public void close() throws Exception {}
+
+ @Override
+ public boolean hasNext() {
+ return false;
+ }
+
+ @Override
+ public SeriesBatchData getNextBatch() {
+ return null;
+ }
+
+ @Override
+ public void open() throws Exception {}
+}
diff --git a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/sink/SinkOperator.java b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/sink/SinkOperator.java
new file mode 100644
index 0000000..29c906d
--- /dev/null
+++ b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/sink/SinkOperator.java
@@ -0,0 +1,28 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.iotdb.cluster.query.distribution.operator.sink;
+
+import org.apache.iotdb.cluster.query.distribution.operator.ExecutableOperator;
+
+// 构建与客户端的联系。
+public abstract class SinkOperator<T> extends ExecutableOperator<T> implements AutoCloseable {
+
+ public abstract void open() throws Exception;
+}
diff --git a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/sink/ThriftSinkOperator.java b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/sink/ThriftSinkOperator.java
new file mode 100644
index 0000000..c9de077
--- /dev/null
+++ b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/sink/ThriftSinkOperator.java
@@ -0,0 +1,41 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.iotdb.cluster.query.distribution.operator.sink;
+
+import org.apache.iotdb.cluster.query.distribution.common.SeriesBatchData;
+
+public class ThriftSinkOperator extends SinkOperator<SeriesBatchData> {
+
+ @Override
+ public void close() throws Exception {}
+
+ @Override
+ public boolean hasNext() {
+ return false;
+ }
+
+ @Override
+ public SeriesBatchData getNextBatch() {
+ return null;
+ }
+
+ @Override
+ public void open() throws Exception {}
+}
diff --git a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/source/CsvSourceOperator.java b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/source/CsvSourceOperator.java
new file mode 100644
index 0000000..ff82128
--- /dev/null
+++ b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/source/CsvSourceOperator.java
@@ -0,0 +1,41 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.iotdb.cluster.query.distribution.operator.source;
+
+import org.apache.iotdb.cluster.query.distribution.common.SeriesBatchData;
+
+public class CsvSourceOperator extends SourceOperator<SeriesBatchData> {
+
+ @Override
+ public void close() throws Exception {}
+
+ @Override
+ public boolean hasNext() {
+ return false;
+ }
+
+ @Override
+ public SeriesBatchData getNextBatch() {
+ return null;
+ }
+
+ @Override
+ public void open() throws Exception {}
+}
diff --git a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/source/SeriesScanOperator.java b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/source/SeriesScanOperator.java
index 9cd6043..fd67f9e 100644
--- a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/source/SeriesScanOperator.java
+++ b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/source/SeriesScanOperator.java
@@ -1,4 +1,4 @@
-package org.apache.iotdb.cluster.query.distribution.operator;
+package org.apache.iotdb.cluster.query.distribution.operator.source;
import org.apache.iotdb.cluster.query.distribution.common.SeriesBatchData;
import org.apache.iotdb.cluster.query.distribution.common.TraversalOrder;
@@ -18,7 +18,7 @@ import org.apache.iotdb.tsfile.read.filter.basic.Filter;
*
* <p>Children type: []
*/
-public class SeriesScanOperator extends InternalOperator<SeriesBatchData> {
+public class SeriesScanOperator extends SourceOperator<SeriesBatchData> {
// The path of the target series which will be scanned.
private Path seriesPath;
@@ -55,4 +55,10 @@ public class SeriesScanOperator extends InternalOperator<SeriesBatchData> {
public Statistics<?> getNextStatisticBetween(TimeRange timeRange) {
return null;
}
+
+ @Override
+ public void close() throws Exception {}
+
+ @Override
+ public void open() throws Exception {}
}
diff --git a/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/source/SourceOperator.java b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/source/SourceOperator.java
new file mode 100644
index 0000000..304cafe
--- /dev/null
+++ b/cluster/src/main/java/org/apache/iotdb/cluster/query/distribution/operator/source/SourceOperator.java
@@ -0,0 +1,28 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.iotdb.cluster.query.distribution.operator.source;
+
+import org.apache.iotdb.cluster.query.distribution.operator.ExecutableOperator;
+
+// 区分不同的数据源，可拓展。
+public abstract class SourceOperator<T> extends ExecutableOperator<T> implements AutoCloseable {
+
+ public abstract void open() throws Exception;
+}