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ambari-server/src/main/java/org/apache/ambari/server/controller/internal/AbstractProviderModule.java (line 684) <https://reviews.apache.org/r/36587/#comment146115> Wont it allow multiple threads to get in? - Sumit Mohanty On July 17, 2015, 11:45 p.m., Sid Wagle wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://reviews.apache.org/r/36587/ > ----------------------------------------------------------- > > (Updated July 17, 2015, 11:45 p.m.) > > > Review request for Ambari, Alejandro Fernandez, Jonathan Hurley, Mahadev > Konar, Myroslav Papirkovskyy, and Sumit Mohanty. > > > Bugs: AMBARI-12453 > https://issues.apache.org/jira/browse/AMBARI-12453 > > > Repository: ambari > > > Description > ------- > > The high level picture seems to be: Requests made from the UI for host > metrics trying to figure out the actual metrics service and the code that > updates in-memory maps which hold information of where that service is and > what ports to use to connect to it etc. These property maps are update by > Observers on important events like Cluster/Service/Host CRUD by resetting a > volatile variable. > > The contention occurs due the thread that actually enters the monitor > protecting the volatile var and asks for another lock on the cluster which is > held by some other thread which also needs a value from the in-memory maps > and waits on the object monitor that it cannot enter. > > Note: Web based deployments get away because not a lot of CRUD ops happen in > parallel to Reads like the use case of monitoring the Blueprint deploy as the > cluster is being provisioned. > > > Diffs > ----- > > > ambari-server/src/main/java/org/apache/ambari/server/controller/internal/AbstractProviderModule.java > 380a0fe > > Diff: https://reviews.apache.org/r/36587/diff/ > > > Testing > ------- > > All unit test passed. > > > Thanks, > > Sid Wagle > >
