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 >> >> >> >
