[IOTDB-29] Fix bug that reading an empty series (but has been registered). (#75)

* fix issue #29

iotdb/src/test/java/org/apache/iotdb/db/integration/IoTDBSeriesReaderIT.java

@@ -19,11 +19,13 @@
 package org.apache.iotdb.db.integration;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.fail;
 
 import java.io.IOException;
 import java.sql.Connection;
 import java.sql.DriverManager;
+import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.Statement;
 import org.apache.iotdb.db.exception.FileNodeManagerException;
@@ -343,4 +345,13 @@ public class IoTDBSeriesReaderIT {
 
     QueryTokenManager.getInstance().endQueryForCurrentRequestThread();
   }
+
+  @Test
+  public void queryEmptySeriesTest() throws SQLException {
+    Statement statement = connection.createStatement();
+    statement.execute("CREATE TIMESERIES root.vehicle.d_empty.s1 WITH DATATYPE=INT64, ENCODING=RLE");
+    ResultSet resultSet = statement.executeQuery("select * from root.vehicle.d_empty");
+    assertFalse (resultSet.next());
+    resultSet.close();
+  }
 }

pom.xml

@@ -201,6 +201,9 @@
                             <exclude>.checkstyle</exclude>
                             <!--Generated by Apache Release -->
                             <exclude>local-snapshots-dir/**</exclude>
+                            <!--IoTDB data files-->
+                            <exclude>iotdb/data/**</exclude>
+                            <exclude>iotdb/logs/**</exclude>
                         </excludes>
                     </configuration>
                 </plugin>

tsfile/src/main/java/org/apache/iotdb/tsfile/read/controller/MetadataQuerier.java

@@ -20,8 +20,10 @@ package org.apache.iotdb.tsfile.read.controller;
 
 import java.io.IOException;
 import java.util.List;
+import org.apache.iotdb.tsfile.exception.write.NoMeasurementException;
 import org.apache.iotdb.tsfile.file.metadata.ChunkMetaData;
 import org.apache.iotdb.tsfile.file.metadata.TsFileMetaData;
+import org.apache.iotdb.tsfile.file.metadata.enums.TSDataType;
 import org.apache.iotdb.tsfile.read.common.Path;
 
 public interface MetadataQuerier {
@@ -38,4 +40,11 @@ public interface MetadataQuerier {
    */
   void loadChunkMetaDatas(List<Path> paths) throws IOException;
 
+  /**
+   *
+   * @param measurement
+   * @return the corresponding data type.
+   * @throws NoMeasurementException if the measurement not exists.
+   */
+  TSDataType getDataType(String measurement) throws NoMeasurementException;
 }

tsfile/src/main/java/org/apache/iotdb/tsfile/read/controller/MetadataQuerierByFileImpl.java

@@ -28,13 +28,16 @@ import java.util.Set;
 import java.util.TreeMap;
 import org.apache.iotdb.tsfile.common.cache.LRUCache;
 import org.apache.iotdb.tsfile.common.constant.QueryConstant;
+import org.apache.iotdb.tsfile.exception.write.NoMeasurementException;
 import org.apache.iotdb.tsfile.file.metadata.ChunkGroupMetaData;
 import org.apache.iotdb.tsfile.file.metadata.ChunkMetaData;
 import org.apache.iotdb.tsfile.file.metadata.TsDeviceMetadata;
 import org.apache.iotdb.tsfile.file.metadata.TsDeviceMetadataIndex;
 import org.apache.iotdb.tsfile.file.metadata.TsFileMetaData;
+import org.apache.iotdb.tsfile.file.metadata.enums.TSDataType;
 import org.apache.iotdb.tsfile.read.TsFileSequenceReader;
 import org.apache.iotdb.tsfile.read.common.Path;
+import org.apache.iotdb.tsfile.write.schema.MeasurementSchema;
 
 public class MetadataQuerierByFileImpl implements MetadataQuerier {
 
@@ -178,6 +181,15 @@ public class MetadataQuerierByFileImpl implements MetadataQuerier {
 
   }
 
+  @Override
+  public TSDataType getDataType(String measurement) throws NoMeasurementException  {
+    MeasurementSchema measurementSchema = fileMetaData.getMeasurementSchema().get(measurement);
+    if(measurementSchema != null) {
+      return measurementSchema.getType();
+    }
+    throw new NoMeasurementException(String.format("%s not found.", measurement));
+  }
+
   private List<ChunkMetaData> loadChunkMetadata(Path path) throws IOException {
 
     if (!fileMetaData.containsDevice(path.getDevice())) {

tsfile/src/main/java/org/apache/iotdb/tsfile/read/query/executor/TsFileExecutor.java

@@ -22,6 +22,7 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 import org.apache.iotdb.tsfile.exception.filter.QueryFilterOptimizationException;
+import org.apache.iotdb.tsfile.exception.write.NoMeasurementException;
 import org.apache.iotdb.tsfile.file.metadata.ChunkMetaData;
 import org.apache.iotdb.tsfile.file.metadata.enums.TSDataType;
 import org.apache.iotdb.tsfile.read.common.Path;
@@ -33,6 +34,7 @@ import org.apache.iotdb.tsfile.read.expression.impl.GlobalTimeExpression;
 import org.apache.iotdb.tsfile.read.expression.util.ExpressionOptimizer;
 import org.apache.iotdb.tsfile.read.query.dataset.DataSetWithoutTimeGenerator;
 import org.apache.iotdb.tsfile.read.query.dataset.QueryDataSet;
+import org.apache.iotdb.tsfile.read.reader.series.EmptyFileSeriesReader;
 import org.apache.iotdb.tsfile.read.reader.series.FileSeriesReader;
 import org.apache.iotdb.tsfile.read.reader.series.FileSeriesReaderWithFilter;
 import org.apache.iotdb.tsfile.read.reader.series.FileSeriesReaderWithoutFilter;
@@ -66,11 +68,15 @@ public class TsFileExecutor implements QueryExecutor {
           return new ExecutorWithTimeGenerator(metadataQuerier, chunkLoader)
               .execute(queryExpression);
         }
-      } catch (QueryFilterOptimizationException e) {
+      } catch (QueryFilterOptimizationException | NoMeasurementException e) {
         throw new IOException(e);
       }
     } else {
-      return execute(queryExpression.getSelectedSeries());
+      try {
+        return execute(queryExpression.getSelectedSeries());
+      } catch (NoMeasurementException e) {
+        throw new IOException(e);
+      }
     }
   }
 
@@ -80,18 +86,9 @@ public class TsFileExecutor implements QueryExecutor {
    * @param selectedPathList all selected paths
    * @return DataSet without TimeGenerator
    */
-  private QueryDataSet execute(List<Path> selectedPathList) throws IOException {
-    List<FileSeriesReader> readersOfSelectedSeries = new ArrayList<>();
-    List<TSDataType> dataTypes = new ArrayList<>();
-
-    for (Path path : selectedPathList) {
-      List<ChunkMetaData> chunkMetaDataList = metadataQuerier.getChunkMetaDataList(path);
-      FileSeriesReader seriesReader = new FileSeriesReaderWithoutFilter(chunkLoader,
-          chunkMetaDataList);
-      readersOfSelectedSeries.add(seriesReader);
-      dataTypes.add(chunkMetaDataList.get(0).getTsDataType());
-    }
-    return new DataSetWithoutTimeGenerator(selectedPathList, dataTypes, readersOfSelectedSeries);
+  private QueryDataSet execute(List<Path> selectedPathList)
+      throws IOException, NoMeasurementException {
+    return executeMayAttachTimeFiler(selectedPathList, null);
   }
 
   /**
@@ -102,18 +99,40 @@ public class TsFileExecutor implements QueryExecutor {
    * @return DataSet without TimeGenerator
    */
   private QueryDataSet execute(List<Path> selectedPathList, GlobalTimeExpression timeFilter)
-      throws IOException {
+      throws IOException, NoMeasurementException {
+    return executeMayAttachTimeFiler(selectedPathList, timeFilter);
+  }
+
+  /**
+   *
+   * @param selectedPathList completed path
+   * @param timeFilter a GlobalTimeExpression or null
+   * @return DataSetWithoutTimeGenerator
+   * @throws IOException
+   * @throws NoMeasurementException
+   */
+  private QueryDataSet executeMayAttachTimeFiler(List<Path> selectedPathList, GlobalTimeExpression timeFilter)
+      throws IOException, NoMeasurementException {
     List<FileSeriesReader> readersOfSelectedSeries = new ArrayList<>();
     List<TSDataType> dataTypes = new ArrayList<>();
 
     for (Path path : selectedPathList) {
       List<ChunkMetaData> chunkMetaDataList = metadataQuerier.getChunkMetaDataList(path);
-      FileSeriesReader seriesReader = new FileSeriesReaderWithFilter(chunkLoader, chunkMetaDataList,
-          timeFilter.getFilter());
+      FileSeriesReader seriesReader;
+      if (chunkMetaDataList.isEmpty()) {
+        seriesReader = new EmptyFileSeriesReader();
+        dataTypes.add(metadataQuerier.getDataType(path.getMeasurement()));
+      } else {
+        if (timeFilter == null) {
+          seriesReader = new FileSeriesReaderWithoutFilter(chunkLoader, chunkMetaDataList);
+        } else {
+          seriesReader = new FileSeriesReaderWithFilter(chunkLoader, chunkMetaDataList,
+              timeFilter.getFilter());
+        }
+        dataTypes.add(chunkMetaDataList.get(0).getTsDataType());
+      }
       readersOfSelectedSeries.add(seriesReader);
-      dataTypes.add(chunkMetaDataList.get(0).getTsDataType());
     }
-
     return new DataSetWithoutTimeGenerator(selectedPathList, dataTypes, readersOfSelectedSeries);
   }
 

tsfile/src/main/java/org/apache/iotdb/tsfile/read/reader/series/EmptyFileSeriesReader.java

+/**
+ * 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.tsfile.read.reader.series;
+
+import org.apache.iotdb.tsfile.file.metadata.ChunkMetaData;
+import org.apache.iotdb.tsfile.read.common.BatchData;
+
+/**
+ * this is for those series which has no data points
+ */
+public class EmptyFileSeriesReader extends FileSeriesReader {
+  BatchData data = new BatchData();
+
+  public EmptyFileSeriesReader() {
+    super(null, null);
+  }
+
+  @Override
+  protected void initChunkReader(ChunkMetaData chunkMetaData) {
+    //do nothing
+  }
+
+  @Override
+  protected boolean chunkSatisfied(ChunkMetaData chunkMetaData) {
+    return false;
+  }
+
+  @Override
+  public boolean hasNextBatch() {
+    return false;
+  }
+
+  @Override
+  public BatchData nextBatch() {
+    return data;
+  }
+
+  @Override
+  public BatchData currentBatch() {
+    return data;
+  }
+
+  @Override
+  public void close() {
+    data = null;
+  }
+}

tsfile/src/test/java/org/apache/iotdb/tsfile/write/TsFileReadWriteTest.java

@@ -19,6 +19,8 @@
 package org.apache.iotdb.tsfile.write;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
 
 import java.io.File;
 import java.io.IOException;
@@ -216,4 +218,38 @@ public class TsFileReadWriteTest {
     reader.close();
   }
 
+  @Test
+  public void readEmptyMeasurementTest() throws IOException, WriteProcessException {
+    String path = "test.tsfile";
+    File f = new File(path);
+    if (f.exists()) {
+      assertTrue(f.delete());
+    }
+    TsFileWriter tsFileWriter = new TsFileWriter(f);
+
+    // add measurements into file schema
+    tsFileWriter
+        .addMeasurement(new MeasurementSchema("sensor_1", TSDataType.FLOAT, TSEncoding.RLE));
+    tsFileWriter
+        .addMeasurement(new MeasurementSchema("sensor_2", TSDataType.INT32, TSEncoding.TS_2DIFF));
+    // construct TSRecord
+    TSRecord tsRecord = new TSRecord(1, "device_1");
+    DataPoint dPoint1 = new FloatDataPoint("sensor_1", 1.2f);
+    tsRecord.addTuple(dPoint1);
+    // write a TSRecord to TsFile
+    tsFileWriter.write(tsRecord);
+    // close TsFile
+    tsFileWriter.close();
+
+    // read example : no filter
+    TsFileSequenceReader reader = new TsFileSequenceReader(path);
+    ReadOnlyTsFile readTsFile = new ReadOnlyTsFile(reader);
+    ArrayList<Path> paths = new ArrayList<>();
+    paths.add(new Path("device_1.sensor_2"));
+    QueryExpression queryExpression = QueryExpression.create(paths, null);
+    QueryDataSet queryDataSet = readTsFile.query(queryExpression);
+    assertFalse(queryDataSet.hasNext());
+    reader.close();
+    assertTrue(f.delete());
+  }
 }