Gopal V created HDFS-14345:
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             Summary: fs.BufferedFSInputStream::read is synchronized
                 Key: HDFS-14345
                 URL: https://issues.apache.org/jira/browse/HDFS-14345
             Project: Hadoop HDFS
          Issue Type: Bug
            Reporter: Gopal V


BufferedInputStream::read() has performance issues - this can be fixed by 
wrapping the stream in another non-synchronized buffered inputstream, but that 
incurs memory copy overheads and is sub-optimal.

https://github.com/openjdk/jdk/blob/master/src/java.base/share/classes/java/io/BufferedInputStream.java#L269

Hadoop fs streams aren't thread-safe (except for ReadFully) and are stateful 
for position, so this synchronization is purely a tax without benefit.



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