Above issue is now fixed with commit revision: fe0e6f81a673d6db815a56a3592c41441c4be3ae
On Tue, Jan 20, 2015 at 7:03 PM, Imesh Gunaratne <[email protected]> wrote: > Following JIRA explains the above problem found in 4.1.0-alpha: > https://issues.apache.org/jira/browse/STRATOS-1089 > > On Tue, Jan 20, 2015 at 6:50 PM, Imesh Gunaratne <[email protected]> wrote: > >> Hi Devs, >> >> Currently we have significant amount of read write locks in Stratos >> codebase to synchronize data structure updates made by multiple threads. >> >> As I figured out recently there are several possibilities that these >> locks could cause problems if not properly implemented: >> >> *Problem 1: A thread trying to acquire a write lock while having a read >> lock.* >> *Problem 2: Locks acquired but not released* >> >> I just implemented a ReadWriteLock class in stratos common module which >> could detect these problems. This class make use >> of java.util.concurrent.locks.ReentrantReadWriteLock and implements >> additional logic to detect problems. By default problem 2 detection logic >> is disabled, it can be enabled by setting following system property: >> >> >> *read.write.lock.monitor.enabled=true* >> >> I have now updated all read write locks with the above class. >> Following is an example scenario where I detected an unreleased lock in >> the REST API: >> >> org.apache.stratos.common.exception.LockNotReleasedException >> at >> org.apache.stratos.common.concurrent.locks.ReadWriteLockMonitor.checkTimeout(ReadWriteLockMonitor.java:71) >> at >> org.apache.stratos.common.concurrent.locks.ReadWriteLockMonitor.run(ReadWriteLockMonitor.java:50) >> at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) >> at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:304) >> at >> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:178) >> at >> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293) >> at >> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) >> at >> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) >> at java.lang.Thread.run(Thread.java:745) >> [2015-01-20 18:30:12,952] ERROR >> {org.apache.stratos.common.concurrent.locks.ReadWriteLockMonitor} - System >> error, lock has not released for 30 seconds: [lock-name] topology >> [lock-type] Read [thread-id] 405 [thread-name] http-nio-9443-exec-21 >> [stack-trace] >> java.lang.Thread.getStackTrace(Thread.java:1589) >> >> org.apache.stratos.common.concurrent.locks.ReadWriteLock.acquireReadLock(ReadWriteLock.java:160) >> >> org.apache.stratos.messaging.message.receiver.topology.TopologyManager.acquireReadLockForCluster(TopologyManager.java:173) >> >> org.apache.stratos.rest.endpoint.api.StratosApiV41Utils.addClustersInstancesToGroupInstanceBean(StratosApiV41Utils.java:1015) >> >> org.apache.stratos.rest.endpoint.api.StratosApiV41Utils.setSubGroupInstances(StratosApiV41Utils.java:1027) >> >> org.apache.stratos.rest.endpoint.api.StratosApiV41Utils.addGroupsInstancesToApplicationInstanceBean(StratosApiV41Utils.java:979) >> >> org.apache.stratos.rest.endpoint.api.StratosApiV41Utils.getApplicationRuntime(StratosApiV41Utils.java:963) >> >> org.apache.stratos.rest.endpoint.api.StratosApiV41.getApplicationRuntime(StratosApiV41.java:579) >> >> Thanks >> >> >> -- >> Imesh Gunaratne >> >> Technical Lead, WSO2 >> Committer & PMC Member, Apache Stratos >> > > > > -- > Imesh Gunaratne > > Technical Lead, WSO2 > Committer & PMC Member, Apache Stratos > -- Imesh Gunaratne Technical Lead, WSO2 Committer & PMC Member, Apache Stratos
