And, missed mentioning that when this this race condition / state corruption happens all "get" operations performed on Set/Map get blocked resulting in OOM situation. [1 <http://mailinator.blogspot.gr/2009/06/beautiful-race-condition.html>] has all that explained nicely. I have checked a heap dump in a similar situation and if you take one, you will clearly see many threads waiting to access this Set instance.
[1] http://mailinator.blogspot.gr/2009/06/beautiful-race-condition.html On Wed, Dec 16, 2015 at 5:37 PM, Ayoma Wijethunga <[email protected]> wrote: > Hi Anjana, > > Sorry, I didn't notice that you have already replied this thread. > > However, please consider my point on "getAllIndexedTables" as well. > > Thank you, > Ayoma. > > On Wed, Dec 16, 2015 at 5:12 PM, Anjana Fernando <[email protected]> wrote: > >> Hi Sumedha, >> >> Thank you for reporting the issue. I've fixed the concurrent modification >> exception issue, where, actually both the methods "addIndexedTable" and >> "removeIndexedTable" needed to be synchronized, since they both work on the >> shared Set object there. >> >> As for the OOM issue, can you please share a heap dump when the OOM >> happened. So we can see what is causing this. And also, I see there are >> multiple scripts running at the same time, so this actually can be a >> legitimate error also, where the server actually doesn't have enough memory >> to continue its operations. @Niranda, please share if there is any info on >> tuning Spark's memory requirements. >> >> Cheers, >> Anjana. >> >> On Wed, Dec 16, 2015 at 3:32 PM, Sumedha Rubasinghe <[email protected]> >> wrote: >> >>> We have DAS Lite included in IoT Server and several summarisation >>> scripts deployed. Server is going OOM frequently with following exception. >>> >>> Shouldn't this[1] method be synchronised? >>> >>> [1] >>> https://github.com/wso2/carbon-analytics/blob/master/components/analytics-core/org.wso2.carbon.analytics.dataservice.core/src/main/java/org/wso2/carbon/analytics/dataservice/core/indexing/AnalyticsIndexedTableStore.java#L45 >>> >>> >>> >>>>>>>>>>> >>> [2015-12-16 15:11:00,004] INFO >>> {org.wso2.carbon.analytics.spark.core.AnalyticsTask} - Executing the >>> schedule task for: Light_Sensor_Script for tenant id: -1234 >>> [2015-12-16 15:11:00,005] INFO >>> {org.wso2.carbon.analytics.spark.core.AnalyticsTask} - Executing the >>> schedule task for: Magnetic_Sensor_Script for tenant id: -1234 >>> [2015-12-16 15:11:00,005] INFO >>> {org.wso2.carbon.analytics.spark.core.AnalyticsTask} - Executing the >>> schedule task for: Pressure_Sensor_Script for tenant id: -1234 >>> [2015-12-16 15:11:00,006] INFO >>> {org.wso2.carbon.analytics.spark.core.AnalyticsTask} - Executing the >>> schedule task for: Proximity_Sensor_Script for tenant id: -1234 >>> [2015-12-16 15:11:00,006] INFO >>> {org.wso2.carbon.analytics.spark.core.AnalyticsTask} - Executing the >>> schedule task for: Rotation_Sensor_Script for tenant id: -1234 >>> [2015-12-16 15:11:00,007] INFO >>> {org.wso2.carbon.analytics.spark.core.AnalyticsTask} - Executing the >>> schedule task for: Temperature_Sensor_Script for tenant id: -1234 >>> [2015-12-16 15:11:01,132] ERROR >>> {org.wso2.carbon.ntask.core.impl.TaskQuartzJobAdapter} - Error in >>> executing task: null >>> java.util.ConcurrentModificationException >>> at java.util.HashMap$HashIterator.nextEntry(HashMap.java:922) >>> at java.util.HashMap$KeyIterator.next(HashMap.java:956) >>> at java.util.AbstractCollection.toArray(AbstractCollection.java:195) >>> at >>> org.wso2.carbon.analytics.dataservice.core.indexing.AnalyticsIndexedTableStore.refreshIndexedTableArray(AnalyticsIndexedTableStore.java:46) >>> at >>> org.wso2.carbon.analytics.dataservice.core.indexing.AnalyticsIndexedTableStore.addIndexedTable(AnalyticsIndexedTableStore.java:37) >>> at >>> org.wso2.carbon.analytics.dataservice.core.AnalyticsDataServiceImpl.refreshIndexedTableStoreEntry(AnalyticsDataServiceImpl.java:512) >>> at >>> org.wso2.carbon.analytics.dataservice.core.AnalyticsDataServiceImpl.invalidateAnalyticsTableInfo(AnalyticsDataServiceImpl.java:525) >>> at >>> org.wso2.carbon.analytics.dataservice.core.AnalyticsDataServiceImpl.checkAndInvalidateTableInfo(AnalyticsDataServiceImpl.java:504) >>> at >>> org.wso2.carbon.analytics.dataservice.core.AnalyticsDataServiceImpl.setTableSchema(AnalyticsDataServiceImpl.java:495) >>> at >>> org.wso2.carbon.analytics.spark.core.sources.AnalyticsRelation.insert(AnalyticsRelation.java:162) >>> at >>> org.apache.spark.sql.sources.InsertIntoDataSource.run(commands.scala:53) >>> at >>> org.apache.spark.sql.execution.ExecutedCommand.sideEffectResult$lzycompute(commands.scala:57) >>> at >>> org.apache.spark.sql.execution.ExecutedCommand.sideEffectResult(commands.scala:57) >>> at >>> org.apache.spark.sql.execution.ExecutedCommand.doExecute(commands.scala:68) >>> at >>> org.apache.spark.sql.execution.SparkPlan$$anonfun$execute$1.apply(SparkPlan.scala:88) >>> at >>> org.apache.spark.sql.execution.SparkPlan$$anonfun$execute$1.apply(SparkPlan.scala:88) >>> at >>> org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:147) >>> at org.apache.spark.sql.execution.SparkPlan.execute(SparkPlan.scala:87) >>> at >>> org.apache.spark.sql.SQLContext$QueryExecution.toRdd$lzycompute(SQLContext.scala:950) >>> at >>> org.apache.spark.sql.SQLContext$QueryExecution.toRdd(SQLContext.scala:950) >>> at org.apache.spark.sql.DataFrame.<init>(DataFrame.scala:144) >>> at org.apache.spark.sql.DataFrame.<init>(DataFrame.scala:128) >>> at org.apache.spark.sql.DataFrame$.apply(DataFrame.scala:51) >>> at org.apache.spark.sql.SQLContext.sql(SQLContext.scala:755) >>> at >>> org.wso2.carbon.analytics.spark.core.internal.SparkAnalyticsExecutor.executeQueryLocal(SparkAnalyticsExecutor.java:710) >>> at >>> org.wso2.carbon.analytics.spark.core.internal.SparkAnalyticsExecutor.executeQuery(SparkAnalyticsExecutor.java:692) >>> at >>> org.wso2.carbon.analytics.spark.core.CarbonAnalyticsProcessorService.executeQuery(CarbonAnalyticsProcessorService.java:199) >>> at >>> org.wso2.carbon.analytics.spark.core.CarbonAnalyticsProcessorService.executeScript(CarbonAnalyticsProcessorService.java:149) >>> at >>> org.wso2.carbon.analytics.spark.core.AnalyticsTask.execute(AnalyticsTask.java:57) >>> at >>> org.wso2.carbon.ntask.core.impl.TaskQuartzJobAdapter.execute(TaskQuartzJobAdapter.java:67) >>> at org.quartz.core.JobRunShell.run(JobRunShell.java:213) >>> at >>> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) >>> at java.util.concurrent.FutureTask.run(FutureTask.java:262) >>> at >>> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) >>> at >>> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) >>> at java.lang.Thread.run(Thread.java:745) >>> [2015-12-16 15:12:00,001] INFO >>> {org.wso2.carbon.analytics.spark.core.AnalyticsTask} - Executing the >>> schedule task for: Accelerometer_Sensor_Script for tenant id: -1234 >>> >>> -- >>> /sumedha >>> m: +94 773017743 >>> b : bit.ly/sumedha >>> >> >> >> >> -- >> *Anjana Fernando* >> Senior Technical Lead >> WSO2 Inc. | http://wso2.com >> lean . enterprise . middleware >> >> _______________________________________________ >> Dev mailing list >> [email protected] >> http://wso2.org/cgi-bin/mailman/listinfo/dev >> >> > > > -- > Ayoma Wijethunga > Software Engineer > WSO2, Inc.; http://wso2.com > lean.enterprise.middleware > > Mobile : +94 (0) 719428123 <+94+(0)+719428123> > Blog : http://www.ayomaonline.com > LinkedIn: https://www.linkedin.com/in/ayoma > -- Ayoma Wijethunga Software Engineer WSO2, Inc.; http://wso2.com lean.enterprise.middleware Mobile : +94 (0) 719428123 <+94+(0)+719428123> Blog : http://www.ayomaonline.com LinkedIn: https://www.linkedin.com/in/ayoma
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