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Colin Patrick McCabe commented on HDFS-5644: -------------------------------------------- libhdfs doesn't actually use locking to get the JNI environment. It uses thread-local data for that, since you need a different {{JNIEnv}} per thread. The shared hash table stores global class references. Since this is insert-only (we never remove elements), and we should not need to resize this if we choose the initial size properly, it would be relatively easy to create a concurrent version of this. > Reduce lock contention in libhdfs. > ---------------------------------- > > Key: HDFS-5644 > URL: https://issues.apache.org/jira/browse/HDFS-5644 > Project: Hadoop HDFS > Issue Type: Improvement > Components: libhdfs > Affects Versions: 3.0.0, 2.2.0 > Reporter: Chris Nauroth > > libhdfs uses locking internally for coordinating access to shared hash tables > and the JNI environment. The scope of this issue is to improve performance > of libhdfs by reducing lock contention. -- This message was sent by Atlassian JIRA (v6.1.4#6159)