It looks great! Thanks Mari! On Wed, Jun 24, 2015 at 6:02 PM, Mariangela Hills <mariang...@wso2.com> wrote:
> Hi Devs, > > I added this information in [1] in the developer guide. Please let me know > whether any changes are needed. > > [1] > https://cwiki.apache.org/confluence/display/STRATOS/Detecting+Issues+with+Read-Write+Locks > [2] https://issues.apache.org/jira/browse/STRATOS-1439 > > Regards, > Mariangela > > > *Mariangela Hills* > Senior Technical Writer - WSO2, Inc. http://wso2.com > Committer and PMC member - Apache Stratos > email:mariang...@wso2.com | mobile: +94 773 500185 > > On Wed, Jun 24, 2015 at 3:10 PM, Mariangela Hills <mariang...@wso2.com> > wrote: > >> Will do! >> >> Regards, >> Mariangela >> >> >> *Mariangela Hills* >> Senior Technical Writer - WSO2, Inc. http://wso2.com >> Committer and PMC member - Apache Stratos >> email:mariang...@wso2.com | mobile: +94 773 500185 >> >> On Wed, Jun 24, 2015 at 2:43 PM, Reka Thirunavukkarasu <r...@wso2.com> >> wrote: >> >>> Thanks for implementing this nice feature Imesh. This helps a lot in >>> identifying the locking issues. >>> >>> @Mari, >>> >>> Can we add this to our documentation under developer guide or >>> troubleshoot section? So that it will help in debugging purpose. >>> >>> Thanks, >>> Reka >>> >>> On Tue, Jan 20, 2015 at 10:26 PM, Dakshika Jayathilaka < >>> daksh...@wso2.com> wrote: >>> >>>> Great Work imesh.. This will help to developers in many ways.. >>>> >>>> Better if we can add this to developer guide. >>>> >>>> *Dakshika Jayathilaka* >>>> Software Engineer >>>> WSO2, Inc. >>>> lean.enterprise.middleware >>>> 0771100911 >>>> >>>> On Tue, Jan 20, 2015 at 7:08 PM, Imesh Gunaratne <im...@apache.org> >>>> wrote: >>>> >>>>> Above issue is now fixed with commit revision: >>>>> fe0e6f81a673d6db815a56a3592c41441c4be3ae >>>>> >>>>> On Tue, Jan 20, 2015 at 7:03 PM, Imesh Gunaratne <im...@apache.org> >>>>> 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 <im...@apache.org> >>>>>> 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 >>>>> >>>> >>>> >>> >>> >>> -- >>> Reka Thirunavukkarasu >>> Senior Software Engineer, >>> WSO2, Inc.:http://wso2.com, >>> Mobile: +94776442007 >>> >>> >>> >> > -- Imesh Gunaratne Senior Technical Lead, WSO2 Committer & PMC Member, Apache Stratos
