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  1. Hadoop HDFS
  2. HDFS-14820

The default 8KB buffer of BlockReaderRemote#newBlockReader#BufferedOutputStream is too big

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    Details

    • Type: Bug
    • Status: Resolved
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 3.3.0
    • Component/s: None
    • Labels:
      None
    • Release Note:
      Reduce the output stream buffer size of a DFSClient remote read from 8KB to 512 bytes.

      Description

      this issue is similar to HDFS-14535.

      public static BlockReader newBlockReader(String file,
          ExtendedBlock block,
          Token<BlockTokenIdentifier> blockToken,
          long startOffset, long len,
          boolean verifyChecksum,
          String clientName,
          Peer peer, DatanodeID datanodeID,
          PeerCache peerCache,
          CachingStrategy cachingStrategy,
          int networkDistance) throws IOException {
        // in and out will be closed when sock is closed (by the caller)
        final DataOutputStream out = new DataOutputStream(new BufferedOutputStream(
            peer.getOutputStream()));
        new Sender(out).readBlock(block, blockToken, clientName, startOffset, len,
            verifyChecksum, cachingStrategy);
      }
      
      public BufferedOutputStream(OutputStream out) {
          this(out, 8192);
      }
      

      Sender#readBlock parameter( block,blockToken, clientName, startOffset, len, verifyChecksum, cachingStrategy) could not use such a big buffer.
      So i think it should reduce BufferedOutputStream buffer.

        Attachments

        1. HDFS-14820.003.patch
          3 kB
          Lisheng Sun
        2. HDFS-14820.002.patch
          2 kB
          Lisheng Sun
        3. HDFS-14820.001.patch
          3 kB
          Lisheng Sun

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              • Assignee:
                leosun08 Lisheng Sun
                Reporter:
                leosun08 Lisheng Sun
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                Dates

                • Created:
                  Updated:
                  Resolved: