jt2594838 commented on a change in pull request #258: [IOTDB-143]Development of merge URL: https://github.com/apache/incubator-iotdb/pull/258#discussion_r314569883
########## File path: server/src/main/java/org/apache/iotdb/db/engine/merge/manage/MergeResource.java ########## @@ -0,0 +1,254 @@ +/** + * 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.engine.merge.manage; + +import static org.apache.iotdb.db.engine.merge.task.MergeTask.MERGE_SUFFIX; + +import java.io.File; +import java.io.IOException; +import java.util.ArrayList; +import java.util.HashMap; +import java.util.Iterator; +import java.util.LinkedList; +import java.util.List; +import java.util.Map; +import java.util.Map.Entry; +import java.util.stream.Collectors; +import org.apache.iotdb.db.engine.modification.Modification; +import org.apache.iotdb.db.engine.storagegroup.TsFileResource; +import org.apache.iotdb.db.query.context.QueryContext; +import org.apache.iotdb.db.query.reader.IPointReader; +import org.apache.iotdb.db.query.reader.resourceRelated.CachedUnseqResourceMergeReader; +import org.apache.iotdb.db.utils.MergeUtils; +import org.apache.iotdb.tsfile.common.conf.TSFileConfig; +import org.apache.iotdb.tsfile.file.metadata.ChunkMetaData; +import org.apache.iotdb.tsfile.file.metadata.enums.TSDataType; +import org.apache.iotdb.tsfile.read.TsFileSequenceReader; +import org.apache.iotdb.tsfile.read.common.Chunk; +import org.apache.iotdb.tsfile.read.common.Path; +import org.apache.iotdb.tsfile.write.chunk.ChunkBuffer; +import org.apache.iotdb.tsfile.write.chunk.ChunkWriterImpl; +import org.apache.iotdb.tsfile.write.chunk.IChunkWriter; +import org.apache.iotdb.tsfile.write.schema.MeasurementSchema; +import org.apache.iotdb.tsfile.write.writer.RestorableTsFileIOWriter; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * MergeResource manages files and caches of readers, writers, MeasurementSchemas and + * modifications to avoid unnecessary object creations and file openings. + */ +public class MergeResource { + + private static final Logger logger = LoggerFactory.getLogger(MergeResource.class); + + private List<TsFileResource> seqFiles; + private List<TsFileResource> unseqFiles; + + private QueryContext mergeContext = new QueryContext(); + + private Map<TsFileResource, TsFileSequenceReader> fileReaderCache; Review comment: This coupling hardly brings any merit. It may save some time reading TsFileMetadata, but it is relatively small compared to the MergeTask itself. And the chance you are merging a file that is being queried is not that big too, so I prefer to decouple it from other modules. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
