Zinan Zhuang created HDFS-17553:
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Summary: DFSOutputStream.java#closeImpl should have a retry upon
flushInternal failures
Key: HDFS-17553
URL: https://issues.apache.org/jira/browse/HDFS-17553
Project: Hadoop HDFS
Issue Type: Improvement
Components: dfsclient
Affects Versions: 3.4.0, 3.3.1
Reporter: Zinan Zhuang
[HDFS-15865|https://issues.apache.org/jira/browse/HDFS-15865] introduced an
interrupt in DFSStreamer class to interrupt the
waitForAckedSeqno call when timeout has exceeded. This method is being used in
[DFSOutputStream.java#flushInternal
|https://github.com/apache/hadoop/blob/branch-3.0.0/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSOutputStream.java#L773]
, one of whose use case is
[DFSOutputStream.java#closeImpl|https://github.com/apache/hadoop/blob/branch-3.0.0/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSOutputStream.java#L870]
to close a file.
What we saw was that we were getting more interrupts during the flushInternal
call when we are closing out a file, which was unhandled by DFSClient and got
thrown to caller. There's a known issue
[HDFS-4504|https://issues.apache.org/jira/browse/HDFS-4504] that when a file
failed to close on HDFS side, the lease got leaked until the DFSClient gets
recycled. In our HBase setups, DFSClients remain long-lived in each
regionserver, which means these files remain undead until the regionserver gets
restarted.
This issue was observed during datanode decomission because it was stuck on
open files caused by above leakage. As it's good to close a HDFS file as smooth
as possible, a retry of flushInternal during closeImpl operations would be
beneficial to reduce such leakages.
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