[GitHub] little-emotion commented on a change in pull request #79: [IOTDB-6]Value filter query optimization

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little-emotion commented on a change in pull request #79: [IOTDB-6]Value filter query optimization
URL: https://github.com/apache/incubator-iotdb/pull/79#discussion_r261574495
 
 

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 File path: iotdb/src/main/java/org/apache/iotdb/db/query/reader/sequence/SealedTsFilesReaderByTimestamp.java
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+/**
+ * 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.reader.sequence;
+
+import java.io.IOException;
+import java.util.List;
+import org.apache.iotdb.db.engine.filenode.IntervalFileNode;
+import org.apache.iotdb.db.engine.modification.Modification;
+import org.apache.iotdb.db.query.context.QueryContext;
+import org.apache.iotdb.db.query.control.FileReaderManager;
+import org.apache.iotdb.db.query.reader.merge.EngineReaderByTimeStamp;
+import org.apache.iotdb.db.utils.QueryUtils;
+import org.apache.iotdb.tsfile.file.metadata.ChunkMetaData;
+import org.apache.iotdb.tsfile.read.TsFileSequenceReader;
+import org.apache.iotdb.tsfile.read.common.Path;
+import org.apache.iotdb.tsfile.read.controller.ChunkLoader;
+import org.apache.iotdb.tsfile.read.controller.ChunkLoaderImpl;
+import org.apache.iotdb.tsfile.read.controller.MetadataQuerierByFileImpl;
+import org.apache.iotdb.tsfile.read.reader.series.SeriesReaderByTimestamp;
+
+public class SealedTsFilesReaderByTimestamp implements EngineReaderByTimeStamp {
+
+  private Path seriesPath;
+  private List<IntervalFileNode> sealedTsFiles;
+  private int usedIntervalFileIndex;
+  private SeriesReaderByTimestamp seriesReader;
+  private QueryContext context;
+
+  /**
+   * init with seriesPath and sealedTsFiles.
+   */
+  public SealedTsFilesReaderByTimestamp(Path seriesPath, List<IntervalFileNode> sealedTsFiles,
+      QueryContext context) {
+    this.seriesPath = seriesPath;
+    this.sealedTsFiles = sealedTsFiles;
+    this.usedIntervalFileIndex = 0;
+    this.seriesReader = null;
+    this.context = context;
+  }
+
+  @Override
+  public Object getValueInTimestamp(long timestamp) throws IOException {
+    Object value = null;
+    if (seriesReader != null) {
+      value = seriesReader.getValueInTimestamp(timestamp);
+      if (value != null || seriesReader.hasNext()) {
+        return value;
+      }
+    }
+    constructReader(timestamp);
+    if (seriesReader != null) {
+      value = seriesReader.getValueInTimestamp(timestamp);
+      if (value != null || seriesReader.hasNext()) {
+        return value;
+      }
+    }
+
+    return value;
+  }
+
+  @Override
+  public boolean hasNext() throws IOException {
+    if (seriesReader != null && seriesReader.hasNext()) {
+      return true;
+    }
+    return usedIntervalFileIndex + 1 < sealedTsFiles.size();
 
 Review comment:
   hasNext() method is used to judge whether to skip this reader.  If there is no data in 5th file, it will not skip. But when you get a larger timestamp point next time, it finds no data in 5th file, then it will skip this reader.Although it works,  I have changed it to make the procedure more rigorous.
   

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