Hi, I am using flink sql 1.5.0. My application throws NPE. And after it recover from checkpoint automatically, it throws NPE immediately from same line of code.
My application read message from kafka, convert the datastream into a table, issue an Over-window aggregation and write the result into a sink. NPE throws from class ProcTimeBoundedRangeOver. Please see exception log at the bottom. The exceptions always happens after the application started for maxIdleStateRetentionTime time. What could be the possible causes? Best Yan 2018-05-27 11:03:37,656 INFO org.apache.flink.runtime.taskmanager.Task - over: (PARTITION BY: uid, ORDER BY: proctime, RANGEBETWEEN 86400000 PRECEDI NG AND CURRENT ROW, select: (id, uid, proctime, group_concat($7) AS w0$o0)) -> select: (id, uid, proctime, w0$o0 AS EXPR$3) -> to: Row -> Flat Map -> Filter -> Sink: Unnamed (3/15) (327 efe96243bbfdf1f1e40a3372f64aa) switched from RUNNING to FAILED. TimerException{java.lang.NullPointerException} at org.apache.flink.streaming.runtime.tasks.SystemProcessingTimeService$TriggerTask.run(SystemProcessingTimeService.java:284) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180) at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:748) Caused by: java.lang.NullPointerException at org.apache.flink.table.runtime.aggregate.ProcTimeBoundedRangeOverWithLog.onTimer(ProcTimeBoundedRangeOver.scala:181) at org.apache.flink.streaming.api.operators.LegacyKeyedProcessOperator.invokeUserFunction(LegacyKeyedProcessOperator.java:97) at org.apache.flink.streaming.api.operators.LegacyKeyedProcessOperator.onProcessingTime(LegacyKeyedProcessOperator.java:81) at org.apache.flink.streaming.api.operators.HeapInternalTimerService.onProcessingTime(HeapInternalTimerService.java:266) at org.apache.flink.streaming.runtime.tasks.SystemProcessingTimeService$TriggerTask.run(SystemProcessingTimeService.java:281)