[GitHub] [incubator-iotdb] qiaojialin commented on a change in pull request #1204: [IOTDB-622] add count records for all databases

[GitBox <gi...@apache.org>]

qiaojialin commented on a change in pull request #1204:
URL: https://github.com/apache/incubator-iotdb/pull/1204#discussion_r426991499



##########
File path: server/src/main/java/org/apache/iotdb/db/query/dataset/groupby/GroupByLevelDataSet.java
##########
@@ -0,0 +1,217 @@
+/*
+ * 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.db.query.dataset.groupby;
+
+import org.apache.iotdb.db.exception.StorageEngineException;
+import org.apache.iotdb.db.exception.query.QueryProcessException;
+import org.apache.iotdb.db.qp.physical.crud.GroupByPlan;
+import org.apache.iotdb.db.query.aggregation.AggregateResult;
+import org.apache.iotdb.db.query.context.QueryContext;
+import org.apache.iotdb.db.query.factory.AggregateResultFactory;
+import org.apache.iotdb.db.query.filter.TsFileFilter;
+import org.apache.iotdb.tsfile.file.metadata.enums.TSDataType;
+import org.apache.iotdb.tsfile.read.common.Field;
+import org.apache.iotdb.tsfile.read.common.Path;
+import org.apache.iotdb.tsfile.read.common.RowRecord;
+import org.apache.iotdb.tsfile.read.filter.basic.Filter;
+import org.apache.iotdb.tsfile.read.query.dataset.QueryDataSet;
+import org.apache.iotdb.tsfile.utils.Binary;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.util.*;
+
+import static org.apache.iotdb.db.conf.IoTDBConstant.COLUMN_COLUMN;
+import static org.apache.iotdb.db.conf.IoTDBConstant.COLUMN_COUNT;
+
+public class GroupByLevelDataSet extends QueryDataSet {
+
+  private static final Logger logger = LoggerFactory
+    .getLogger(GroupByLevelDataSet.class);
+
+  private List<RowRecord> records = new ArrayList<>();
+  private int index = 0;
+
+  private int level = -1;
+  private boolean isByTime = false;
+  protected long queryId;
+  private GroupByEngineDataSet dataSet;
+  private GroupByPlan groupByPlan;
+  private QueryContext context;
+
+  private Map<Path, GroupByExecutor> pathExecutors = new HashMap<>();
+  private Map<Path, List<Integer>> resultIndexes = new HashMap<>();
+
+  public GroupByLevelDataSet(QueryContext context, GroupByPlan plan, GroupByEngineDataSet dataSet)
+    throws QueryProcessException, StorageEngineException, IOException {
+    this.queryId = context.getQueryId();
+    this.level = plan.getLevel();
+    this.isByTime = plan.isByTime();
+    this.dataSet = dataSet;
+    this.paths = plan.getPaths();
+    this.dataTypes = plan.getDataTypes();
+    this.groupByPlan = plan;
+    this.context = context;
+
+    logger.debug("paths " + this.paths);
+
+    RowRecord record = new RowRecord(0);
+    if (!isByTime) {
+      initGroupBy();
+      record = getRecordWithoutTimeInterval();
+    } else {
+      // get all records from GroupByDataSet, then we merge them to one record
+      logger.debug("only group by level, paths:" + groupByPlan.getPaths());
+      while (dataSet != null && dataSet.hasNextWithoutConstraint()) {
+        RowRecord curRecord = dataSet.nextWithoutConstraint();
+        record = mergeRecords(curRecord, record);
+      }
+    }
+
+    // prepare final records
+    // group by level
+    // path -> count
+    Map<String, Long> finalPaths = new TreeMap<String, Long>();
+
+    for (int j = 0; j < this.paths.size(); j++) {
+      String[] tmpPath = this.paths.get(j).getFullPath().split("\\.");
+
+      String key;
+      if (tmpPath.length <= level) {
+        key = this.paths.get(j).getFullPath();
+      } else {
+        StringBuilder path = new StringBuilder();
+        for (int k = 0; k <= level; k++) {
+          if (k == 0) {
+            path.append(tmpPath[k]);
+          } else {
+            path.append("." + tmpPath[k]);
+          }
+        }
+        key = path.toString();
+      }
+      logger.debug("records " + record.getFields().toString());

Review comment:
       add if (logger.isDebugEnabled())

##########
File path: server/src/main/java/org/apache/iotdb/db/qp/physical/crud/GroupByPlan.java
##########
@@ -33,6 +33,8 @@
   // if it is left close and right open interval
   private boolean leftCRightO = true;
 
+  private boolean byTime = false;

Review comment:
       The GroupByPlan is actually GroupByTimePlan, so no need to add a byTime field, we can rename the class.

##########
File path: server/src/main/java/org/apache/iotdb/db/query/dataset/groupby/GroupByLevelDataSet.java
##########
@@ -0,0 +1,217 @@
+/*
+ * 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.db.query.dataset.groupby;
+
+import org.apache.iotdb.db.exception.StorageEngineException;
+import org.apache.iotdb.db.exception.query.QueryProcessException;
+import org.apache.iotdb.db.qp.physical.crud.GroupByPlan;
+import org.apache.iotdb.db.query.aggregation.AggregateResult;
+import org.apache.iotdb.db.query.context.QueryContext;
+import org.apache.iotdb.db.query.factory.AggregateResultFactory;
+import org.apache.iotdb.db.query.filter.TsFileFilter;
+import org.apache.iotdb.tsfile.file.metadata.enums.TSDataType;
+import org.apache.iotdb.tsfile.read.common.Field;
+import org.apache.iotdb.tsfile.read.common.Path;
+import org.apache.iotdb.tsfile.read.common.RowRecord;
+import org.apache.iotdb.tsfile.read.filter.basic.Filter;
+import org.apache.iotdb.tsfile.read.query.dataset.QueryDataSet;
+import org.apache.iotdb.tsfile.utils.Binary;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.util.*;
+
+import static org.apache.iotdb.db.conf.IoTDBConstant.COLUMN_COLUMN;
+import static org.apache.iotdb.db.conf.IoTDBConstant.COLUMN_COUNT;
+
+public class GroupByLevelDataSet extends QueryDataSet {
+
+  private static final Logger logger = LoggerFactory
+    .getLogger(GroupByLevelDataSet.class);
+
+  private List<RowRecord> records = new ArrayList<>();
+  private int index = 0;
+
+  private int level = -1;
+  private boolean isByTime = false;
+  protected long queryId;
+  private GroupByEngineDataSet dataSet;
+  private GroupByPlan groupByPlan;
+  private QueryContext context;
+
+  private Map<Path, GroupByExecutor> pathExecutors = new HashMap<>();
+  private Map<Path, List<Integer>> resultIndexes = new HashMap<>();
+
+  public GroupByLevelDataSet(QueryContext context, GroupByPlan plan, GroupByEngineDataSet dataSet)
+    throws QueryProcessException, StorageEngineException, IOException {
+    this.queryId = context.getQueryId();
+    this.level = plan.getLevel();
+    this.isByTime = plan.isByTime();
+    this.dataSet = dataSet;
+    this.paths = plan.getPaths();
+    this.dataTypes = plan.getDataTypes();
+    this.groupByPlan = plan;
+    this.context = context;
+
+    logger.debug("paths " + this.paths);
+
+    RowRecord record = new RowRecord(0);
+    if (!isByTime) {
+      initGroupBy();
+      record = getRecordWithoutTimeInterval();
+    } else {
+      // get all records from GroupByDataSet, then we merge them to one record
+      logger.debug("only group by level, paths:" + groupByPlan.getPaths());
+      while (dataSet != null && dataSet.hasNextWithoutConstraint()) {
+        RowRecord curRecord = dataSet.nextWithoutConstraint();
+        record = mergeRecords(curRecord, record);
+      }
+    }
+
+    // prepare final records
+    // group by level
+    // path -> count
+    Map<String, Long> finalPaths = new TreeMap<String, Long>();
+
+    for (int j = 0; j < this.paths.size(); j++) {
+      String[] tmpPath = this.paths.get(j).getFullPath().split("\\.");

Review comment:
       Actually, we support path like this:  root.sg.d."s.1"
   s.1 is measurement name

##########
File path: server/src/main/java/org/apache/iotdb/db/query/dataset/groupby/GroupByLevelDataSet.java
##########
@@ -0,0 +1,217 @@
+/*
+ * 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.db.query.dataset.groupby;
+
+import org.apache.iotdb.db.exception.StorageEngineException;
+import org.apache.iotdb.db.exception.query.QueryProcessException;
+import org.apache.iotdb.db.qp.physical.crud.GroupByPlan;
+import org.apache.iotdb.db.query.aggregation.AggregateResult;
+import org.apache.iotdb.db.query.context.QueryContext;
+import org.apache.iotdb.db.query.factory.AggregateResultFactory;
+import org.apache.iotdb.db.query.filter.TsFileFilter;
+import org.apache.iotdb.tsfile.file.metadata.enums.TSDataType;
+import org.apache.iotdb.tsfile.read.common.Field;
+import org.apache.iotdb.tsfile.read.common.Path;
+import org.apache.iotdb.tsfile.read.common.RowRecord;
+import org.apache.iotdb.tsfile.read.filter.basic.Filter;
+import org.apache.iotdb.tsfile.read.query.dataset.QueryDataSet;
+import org.apache.iotdb.tsfile.utils.Binary;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.util.*;
+
+import static org.apache.iotdb.db.conf.IoTDBConstant.COLUMN_COLUMN;
+import static org.apache.iotdb.db.conf.IoTDBConstant.COLUMN_COUNT;
+
+public class GroupByLevelDataSet extends QueryDataSet {
+
+  private static final Logger logger = LoggerFactory
+    .getLogger(GroupByLevelDataSet.class);
+
+  private List<RowRecord> records = new ArrayList<>();
+  private int index = 0;
+
+  private int level = -1;
+  private boolean isByTime = false;
+  protected long queryId;
+  private GroupByEngineDataSet dataSet;
+  private GroupByPlan groupByPlan;
+  private QueryContext context;
+
+  private Map<Path, GroupByExecutor> pathExecutors = new HashMap<>();
+  private Map<Path, List<Integer>> resultIndexes = new HashMap<>();
+
+  public GroupByLevelDataSet(QueryContext context, GroupByPlan plan, GroupByEngineDataSet dataSet)
+    throws QueryProcessException, StorageEngineException, IOException {
+    this.queryId = context.getQueryId();
+    this.level = plan.getLevel();
+    this.isByTime = plan.isByTime();
+    this.dataSet = dataSet;
+    this.paths = plan.getPaths();
+    this.dataTypes = plan.getDataTypes();
+    this.groupByPlan = plan;
+    this.context = context;
+
+    logger.debug("paths " + this.paths);
+
+    RowRecord record = new RowRecord(0);
+    if (!isByTime) {
+      initGroupBy();
+      record = getRecordWithoutTimeInterval();
+    } else {
+      // get all records from GroupByDataSet, then we merge them to one record
+      logger.debug("only group by level, paths:" + groupByPlan.getPaths());
+      while (dataSet != null && dataSet.hasNextWithoutConstraint()) {
+        RowRecord curRecord = dataSet.nextWithoutConstraint();
+        record = mergeRecords(curRecord, record);
+      }
+    }
+
+    // prepare final records
+    // group by level
+    // path -> count
+    Map<String, Long> finalPaths = new TreeMap<String, Long>();
+
+    for (int j = 0; j < this.paths.size(); j++) {
+      String[] tmpPath = this.paths.get(j).getFullPath().split("\\.");
+
+      String key;
+      if (tmpPath.length <= level) {
+        key = this.paths.get(j).getFullPath();
+      } else {
+        StringBuilder path = new StringBuilder();
+        for (int k = 0; k <= level; k++) {
+          if (k == 0) {
+            path.append(tmpPath[k]);
+          } else {
+            path.append("." + tmpPath[k]);
+          }
+        }
+        key = path.toString();
+      }
+      logger.debug("records " + record.getFields().toString());
+      finalPaths.put(key,
+        record.getFields().get(j).getLongV()
+          + finalPaths.getOrDefault(key, 0L));
+    }
+
+    this.paths = Arrays.asList(new Path(COLUMN_COLUMN), new Path(COLUMN_COUNT));
+    this.dataTypes = Arrays.asList(TSDataType.TEXT, TSDataType.TEXT);
+
+    for (Map.Entry<String, Long> entry : finalPaths.entrySet()) {
+      RowRecord tmpRecord = new RowRecord(0);
+      Field field = new Field(TSDataType.TEXT);
+      field.setBinaryV(new Binary(entry.getKey()));
+      logger.debug("rowRecord " + entry.getKey());
+      Field field1 = new Field(TSDataType.TEXT);
+      field1.setBinaryV(new Binary(Long.toString(entry.getValue())));
+      tmpRecord.addField(field);
+      tmpRecord.addField(field1);
+      records.add(tmpRecord);
+      logger.info(tmpRecord.toString());
+    }
+  }
+
+  @Override
+  protected boolean hasNextWithoutConstraint() throws IOException {
+    return index < records.size();
+  }
+
+  @Override
+  protected RowRecord nextWithoutConstraint() {
+    return records.get(index++);
+  }
+
+  private void initGroupBy()
+    throws QueryProcessException, StorageEngineException {
+    // get all aggregation results, then we package them to one record
+    for (int i = 0; i < paths.size(); i++) {
+      Path path = paths.get(i);
+      if (!pathExecutors.containsKey(path)) {
+        //init GroupByExecutor
+        pathExecutors.put(path,
+          getGroupByExecutor(path, groupByPlan.getAllMeasurementsInDevice(path.getDevice()), dataTypes.get(i), this.context, null, null));
+        resultIndexes.put(path, new ArrayList<>());
+      } else {
+        throw new QueryProcessException("duplicated path found, path:" + path);
+      }
+      resultIndexes.get(path).add(i);
+      AggregateResult aggrResult = AggregateResultFactory
+        .getAggrResultByName(groupByPlan.getDeduplicatedAggregations().get(i), dataTypes.get(i));
+      pathExecutors.get(path).addAggregateResult(aggrResult);
+    }
+  }
+
+  private GroupByExecutor getGroupByExecutor(Path path, Set<String> allSensors, TSDataType dataType,
+                                             QueryContext context, Filter timeFilter, TsFileFilter fileFilter)
+    throws StorageEngineException, QueryProcessException {
+    return new LocalGroupByExecutor(path, allSensors, dataType, context, timeFilter, fileFilter);
+  }
+
+  private RowRecord getRecordWithoutTimeInterval()
+    throws IOException {
+    RowRecord record = new RowRecord(0);
+    AggregateResult[] fields = new AggregateResult[paths.size()];
+
+    try {
+      for (Map.Entry<Path, GroupByExecutor> pathToExecutorEntry : pathExecutors.entrySet()) {
+        GroupByExecutor executor = pathToExecutorEntry.getValue();
+        List<AggregateResult> aggregations = executor.calcResult(Long.MIN_VALUE, Long.MAX_VALUE);
+        for (int i = 0; i < aggregations.size(); i++) {
+          int resultIndex = resultIndexes.get(pathToExecutorEntry.getKey()).get(i);
+          fields[resultIndex] = aggregations.get(i);
+        }
+      }
+    } catch (QueryProcessException e) {
+      logger.error("GroupByWithoutValueFilterDataSet execute has error", e);
+      throw new IOException(e.getMessage(), e);
+    }
+
+    for (AggregateResult res : fields) {
+      if (res == null) {
+        record.addField(null);
+        continue;
+      }
+      record.addField(res.getResult(), res.getResultDataType());
+    }
+    return record;
+  }
+
+  private RowRecord mergeRecords(RowRecord newRecord, RowRecord oldRecord) {

Review comment:
       please add javadoc and an example

##########
File path: server/src/main/java/org/apache/iotdb/db/query/dataset/groupby/GroupByLevelDataSet.java
##########
@@ -0,0 +1,217 @@
+/*
+ * 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.db.query.dataset.groupby;
+
+import org.apache.iotdb.db.exception.StorageEngineException;
+import org.apache.iotdb.db.exception.query.QueryProcessException;
+import org.apache.iotdb.db.qp.physical.crud.GroupByPlan;
+import org.apache.iotdb.db.query.aggregation.AggregateResult;
+import org.apache.iotdb.db.query.context.QueryContext;
+import org.apache.iotdb.db.query.factory.AggregateResultFactory;
+import org.apache.iotdb.db.query.filter.TsFileFilter;
+import org.apache.iotdb.tsfile.file.metadata.enums.TSDataType;
+import org.apache.iotdb.tsfile.read.common.Field;
+import org.apache.iotdb.tsfile.read.common.Path;
+import org.apache.iotdb.tsfile.read.common.RowRecord;
+import org.apache.iotdb.tsfile.read.filter.basic.Filter;
+import org.apache.iotdb.tsfile.read.query.dataset.QueryDataSet;
+import org.apache.iotdb.tsfile.utils.Binary;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.util.*;
+
+import static org.apache.iotdb.db.conf.IoTDBConstant.COLUMN_COLUMN;
+import static org.apache.iotdb.db.conf.IoTDBConstant.COLUMN_COUNT;
+
+public class GroupByLevelDataSet extends QueryDataSet {
+
+  private static final Logger logger = LoggerFactory
+    .getLogger(GroupByLevelDataSet.class);
+
+  private List<RowRecord> records = new ArrayList<>();
+  private int index = 0;
+
+  private int level = -1;
+  private boolean isByTime = false;
+  protected long queryId;
+  private GroupByEngineDataSet dataSet;
+  private GroupByPlan groupByPlan;
+  private QueryContext context;
+
+  private Map<Path, GroupByExecutor> pathExecutors = new HashMap<>();
+  private Map<Path, List<Integer>> resultIndexes = new HashMap<>();
+
+  public GroupByLevelDataSet(QueryContext context, GroupByPlan plan, GroupByEngineDataSet dataSet)
+    throws QueryProcessException, StorageEngineException, IOException {
+    this.queryId = context.getQueryId();
+    this.level = plan.getLevel();
+    this.isByTime = plan.isByTime();
+    this.dataSet = dataSet;
+    this.paths = plan.getPaths();
+    this.dataTypes = plan.getDataTypes();
+    this.groupByPlan = plan;
+    this.context = context;
+
+    logger.debug("paths " + this.paths);
+
+    RowRecord record = new RowRecord(0);
+    if (!isByTime) {
+      initGroupBy();
+      record = getRecordWithoutTimeInterval();
+    } else {
+      // get all records from GroupByDataSet, then we merge them to one record
+      logger.debug("only group by level, paths:" + groupByPlan.getPaths());
+      while (dataSet != null && dataSet.hasNextWithoutConstraint()) {
+        RowRecord curRecord = dataSet.nextWithoutConstraint();
+        record = mergeRecords(curRecord, record);
+      }
+    }
+
+    // prepare final records
+    // group by level
+    // path -> count
+    Map<String, Long> finalPaths = new TreeMap<String, Long>();
+
+    for (int j = 0; j < this.paths.size(); j++) {
+      String[] tmpPath = this.paths.get(j).getFullPath().split("\\.");
+
+      String key;
+      if (tmpPath.length <= level) {
+        key = this.paths.get(j).getFullPath();
+      } else {
+        StringBuilder path = new StringBuilder();
+        for (int k = 0; k <= level; k++) {
+          if (k == 0) {
+            path.append(tmpPath[k]);
+          } else {
+            path.append("." + tmpPath[k]);
+          }
+        }
+        key = path.toString();
+      }
+      logger.debug("records " + record.getFields().toString());
+      finalPaths.put(key,
+        record.getFields().get(j).getLongV()
+          + finalPaths.getOrDefault(key, 0L));
+    }
+
+    this.paths = Arrays.asList(new Path(COLUMN_COLUMN), new Path(COLUMN_COUNT));
+    this.dataTypes = Arrays.asList(TSDataType.TEXT, TSDataType.TEXT);
+
+    for (Map.Entry<String, Long> entry : finalPaths.entrySet()) {
+      RowRecord tmpRecord = new RowRecord(0);
+      Field field = new Field(TSDataType.TEXT);
+      field.setBinaryV(new Binary(entry.getKey()));
+      logger.debug("rowRecord " + entry.getKey());
+      Field field1 = new Field(TSDataType.TEXT);
+      field1.setBinaryV(new Binary(Long.toString(entry.getValue())));
+      tmpRecord.addField(field);
+      tmpRecord.addField(field1);
+      records.add(tmpRecord);
+      logger.info(tmpRecord.toString());
+    }
+  }
+
+  @Override
+  protected boolean hasNextWithoutConstraint() throws IOException {
+    return index < records.size();
+  }
+
+  @Override
+  protected RowRecord nextWithoutConstraint() {
+    return records.get(index++);
+  }
+
+  private void initGroupBy()

Review comment:
       initGroupByLevel? 

##########
File path: server/src/main/java/org/apache/iotdb/db/query/executor/QueryRouter.java
##########
@@ -113,34 +114,45 @@ protected AggregationExecutor getAggregationExecutor(AggregationPlan aggregation
 
   @Override
   public QueryDataSet groupBy(GroupByPlan groupByPlan, QueryContext context)
-      throws QueryFilterOptimizationException, StorageEngineException, QueryProcessException {
-    long unit = groupByPlan.getInterval();
-    long slidingStep = groupByPlan.getSlidingStep();
-    long startTime = groupByPlan.getStartTime();
-    long endTime = groupByPlan.getEndTime();
+    throws QueryFilterOptimizationException, StorageEngineException, QueryProcessException, IOException {
+
+    logger.debug("paths:" + groupByPlan.getPaths() + " level:" + groupByPlan.getLevel() + " byTime:" + groupByPlan.isByTime());

Review comment:
       check if debug enabled

##########
File path: server/src/main/antlr4/org/apache/iotdb/db/qp/strategy/SqlBase.g4
##########
@@ -241,6 +241,13 @@ groupByClause
       COMMA DURATION
       (COMMA DURATION)?
       RR_BRACKET
+    | GROUP BY LEVEL OPERATOR_EQ INT
+    | GROUP BY LR_BRACKET
+            timeInterval
+            COMMA DURATION
+            (COMMA DURATION)?
+            RR_BRACKET
+            COMMA LEVEL OPERATOR_EQ INT

Review comment:
       No need to modify the group by ([1,10), 1ms) clause.

##########
File path: server/src/main/java/org/apache/iotdb/db/query/dataset/groupby/GroupByLevelDataSet.java
##########
@@ -0,0 +1,217 @@
+/*
+ * 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.db.query.dataset.groupby;
+
+import org.apache.iotdb.db.exception.StorageEngineException;
+import org.apache.iotdb.db.exception.query.QueryProcessException;
+import org.apache.iotdb.db.qp.physical.crud.GroupByPlan;
+import org.apache.iotdb.db.query.aggregation.AggregateResult;
+import org.apache.iotdb.db.query.context.QueryContext;
+import org.apache.iotdb.db.query.factory.AggregateResultFactory;
+import org.apache.iotdb.db.query.filter.TsFileFilter;
+import org.apache.iotdb.tsfile.file.metadata.enums.TSDataType;
+import org.apache.iotdb.tsfile.read.common.Field;
+import org.apache.iotdb.tsfile.read.common.Path;
+import org.apache.iotdb.tsfile.read.common.RowRecord;
+import org.apache.iotdb.tsfile.read.filter.basic.Filter;
+import org.apache.iotdb.tsfile.read.query.dataset.QueryDataSet;
+import org.apache.iotdb.tsfile.utils.Binary;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.util.*;
+
+import static org.apache.iotdb.db.conf.IoTDBConstant.COLUMN_COLUMN;
+import static org.apache.iotdb.db.conf.IoTDBConstant.COLUMN_COUNT;
+
+public class GroupByLevelDataSet extends QueryDataSet {
+
+  private static final Logger logger = LoggerFactory
+    .getLogger(GroupByLevelDataSet.class);
+
+  private List<RowRecord> records = new ArrayList<>();
+  private int index = 0;
+
+  private int level = -1;
+  private boolean isByTime = false;
+  protected long queryId;
+  private GroupByEngineDataSet dataSet;
+  private GroupByPlan groupByPlan;

Review comment:
       Replace this with an AggregationPlan

##########
File path: server/src/main/java/org/apache/iotdb/db/qp/strategy/LogicalGenerator.java
##########
@@ -664,6 +668,7 @@ public void enterGroupByFillClause(SqlBaseParser.GroupByFillClauseContext ctx) {
     super.enterGroupByFillClause(ctx);
     queryOp.setGroupBy(true);
     queryOp.setFill(true);
+    queryOp.setGroupByTime(true);

Review comment:
       since there is more than one group by, it's better to use full name.   GroupByLevel and GroupByTime




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