[jira] [Created] (HDFS-12612) DFSStripedOutputStream#close will throw if called a second time with a failed streamer

["Andrew Wang (JIRA)" <ji...@apache.org>]

Andrew Wang created HDFS-12612:
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             Summary: DFSStripedOutputStream#close will throw if called a second time with a failed streamer
                 Key: HDFS-12612
                 URL: https://issues.apache.org/jira/browse/HDFS-12612
             Project: Hadoop HDFS
          Issue Type: Bug
          Components: erasure-coding
    Affects Versions: 3.0.0-beta1
            Reporter: Andrew Wang


Found while testing with Hive. We have a cluster with 2 DNs and the XOR-2-1 policy. If you write a file and call close() twice, it throws this exception:

{noformat}
17/10/04 16:02:14 WARN hdfs.DFSOutputStream: Cannot allocate parity block(index=2, policy=XOR-2-1-1024k). Not enough datanodes? Exclude nodes=[]
...
Caused by: java.io.IOException: Failed to get parity block, index=2
at org.apache.hadoop.hdfs.DFSStripedOutputStream.allocateNewBlock(DFSStripedOutputStream.java:500) ~[hadoop-hdfs-client-3.0.0-alpha3-cdh6.x-SNAPSHOT.jar:?]
at org.apache.hadoop.hdfs.DFSStripedOutputStream.writeChunk(DFSStripedOutputStream.java:524) ~[hadoop-hdfs-client-3.0.0-alpha3-cdh6.x-SNAPSHOT.jar:?]
{noformat}

This is because in DFSStripedOutputStream#closeImpl, if the stream is closed, we throw an exception if any of the striped streamers had an exception:

{code}
  protected synchronized void closeImpl() throws IOException {
    if (isClosed()) {
      final MultipleIOException.Builder b = new MultipleIOException.Builder();
      for(int i = 0; i < streamers.size(); i++) {
        final StripedDataStreamer si = getStripedDataStreamer(i);
        try {
          si.getLastException().check(true);
        } catch (IOException e) {
          b.add(e);
        }
      }
      final IOException ioe = b.build();
      if (ioe != null) {
        throw ioe;
      }
      return;
    }
{code}

I think this is incorrect, since we only need to throw in this situation if we have too many failed streamers. close should also be idempotent, so it should throw the first time we call close if it's going to throw at all.



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