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This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/47305/
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Review request for Ambari, DIPAYAN BHOWMICK, Jonathan Hurley, Mahadev Konar,
and Rohit Choudhary.
Bugs: AMBARI-16146
https://issues.apache.org/jira/browse/AMBARI-16146
Repository: ambari
Description
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Earlier : The synchronized UserLocalConnection.initialValue() was taking time
to get hive connection and all other threads were blocking to get inside this
synchronized block.
In this patch :
1. Removed synchronized from UserLocalConnection.initialValue() and from
UserLocalHiveAuthCredentials.initialValue()
2. Introduced locking on specific key and not the complete method. Key would be
like Connection_INSTANCE-NAME:USER-NAME. So threads for other keys will not get
into contension with this lock. This avoids blocking of thread that do not want
to initialize different keys.
3. Used tryLock and fail with exception if lock cannot be obtained immediately.
This avoids blocking of threads that want to initialize same key as one key
should be initialized only once.
4. corrected synchronization at several places inside UserLocal class.
Diffs
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contrib/views/hive/src/main/java/org/apache/ambari/view/hive/client/UserLocalConnection.java
c80a4c4
contrib/views/hive/src/main/java/org/apache/ambari/view/hive/client/UserLocalHiveAuthCredentials.java
9c72863
contrib/views/utils/src/main/java/org/apache/ambari/view/utils/UserLocal.java
40c8e6e
Diff: https://reviews.apache.org/r/47305/diff/
Testing
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Manual testing done by introducing Thread.sleep in
UserLocalConnection.initialValue() and creating more requests with following
combinations and logs.
0. first thread for connection + user + view combination obtains the lock and
goes inside UserLocalConnection.initialValue() and sleeps
1. same user, same hive view requests for connections fails to get lock with
exception.
2. same user, different hive view -- if first request gets new lock and goes
inside UserLocalConnection.initialValue().
3. same user, different hive view -- if connection created once then works
fine. does not block.
4. different user, same view -- gets new lock and goes inside
UserLocalConnection.initialValue() if first, else works fine.
5. different user, different view -- works as 4.
6. once the first thread come out of initialValue(), rest threads don't try to
get lock and don't fail either, works fine.
Thanks,
Nitiraj Rathore
