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Ship it!




Ship It!

- DIPAYAN BHOWMICK


On May 12, 2016, 2:04 p.m., Nitiraj Rathore wrote:
> 
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> This is an automatically generated e-mail. To reply, visit:
> https://reviews.apache.org/r/47305/
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> 
> (Updated May 12, 2016, 2:04 p.m.)
> 
> 
> Review request for Ambari, DIPAYAN BHOWMICK, Jonathan Hurley, Mahadev Konar, 
> Rohit Choudhary, and Ashwin Rajeev.
> 
> 
> Bugs: AMBARI-16146
>     https://issues.apache.org/jira/browse/AMBARI-16146
> 
> 
> Repository: ambari
> 
> 
> Description
> -------
> 
> 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
> -----
> 
>   
> 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
> -------
> 
> 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
> 
>

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