[GitHub] [incubator-iotdb] qiaojialin commented on a change in pull request #1151: [IOTDB-643] Concurrent queries cause BufferUnderflowException when storage in HDFS

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

qiaojialin commented on a change in pull request #1151:
URL: https://github.com/apache/incubator-iotdb/pull/1151#discussion_r422196308



##########
File path: tsfile/src/main/java/org/apache/iotdb/tsfile/read/TsFileSequenceReader.java
##########
@@ -225,10 +226,13 @@ public String readHeadMagic() throws IOException {
    * to the end of the magic head string.
    */
   public String readHeadMagic(boolean movePosition) throws IOException {

Review comment:
       this parameter is no need ,  the tsfileInput is positioned in selfcheck already.

##########
File path: server/src/main/java/org/apache/iotdb/db/engine/cache/ChunkMetadataCache.java
##########
@@ -100,18 +100,24 @@ public static ChunkMetadataCache getInstance() {
   public List<ChunkMetadata> get(String filePath, Path seriesPath)
       throws IOException {
     if (!cacheEnable) {
-      // bloom filter part
-      TsFileSequenceReader tsFileReader = FileReaderManager.getInstance().get(filePath, true);
-      BloomFilter bloomFilter = tsFileReader.readBloomFilter();
-      if (bloomFilter != null && !bloomFilter.contains(seriesPath.getFullPath())) {
-        if (logger.isDebugEnabled()) {
-          logger.debug(String
-              .format("path not found by bloom filter, file is: %s, path is: %s", filePath, seriesPath));
+      lock.writeLock().lock();

Review comment:
       why add this lock?  the lock is for concurrently modify lruCache

##########
File path: hadoop/src/main/java/org/apache/iotdb/hadoop/fileSystem/HDFSInput.java
##########
@@ -68,26 +60,26 @@ public long position() throws IOException {
   }
 
   @Override
-  public TsFileInput position(long newPosition) throws IOException {
+  public synchronized TsFileInput position(long newPosition) throws IOException {

Review comment:
       this function should be used cautiously, it's better to use the read(position, length)




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