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pengfei.zhan commented on KYLIN-5762: ------------------------------------- h1. Root Cause The parameter `kylin.job.max-concurrent-jobs ` can be set to 0. For example: The value of this parameter was not 0 when KYLIN was started. Later, the user created a batch of tasks, but the user did not want these tasks to be scheduled, so the value of this parameter was modified to 0 in the project parameter setting module. Next, maybe due to some problems, the user restarts the KYLIN system and finds the system scheduled task scheduling is abnormal. When restarting the KYLIN, the core pool size is 0, creating jobPool throws IllegalArgumentException for the maximumPoolSize can not be 0. Due to the initialization of Job scheduler failed, the ExecutableContext is null. When scheduling tasks, both the jobPool and the executableContext are null, the NPE throws. {code:java} // job scheduler corePoolSize int corePoolSize = getMaxConcurrentJobLimitByProject(config, jobEngineConfig, project); jobPool = new ThreadPoolExecutor(corePoolSize, corePoolSize, Long.MAX_VALUE, TimeUnit.DAYS, new SynchronousQueue<>(), new NamedThreadFactory("RunJobWorker(project:" + project + ")")); context = new ExecutableContext(Maps.newConcurrentMap(), Maps.newConcurrentMap(), jobEngineConfig.getConfig(), epochId);{code} On the job page we will find that all tasks are suspended. If we restart these tasks, NPE will be thrown. > Initialize job scheduler encounters NPE > --------------------------------------- > > Key: KYLIN-5762 > URL: https://issues.apache.org/jira/browse/KYLIN-5762 > Project: Kylin > Issue Type: Bug > Components: Job Engine > Affects Versions: 5.0-beta > Reporter: pengfei.zhan > Assignee: pengfei.zhan > Priority: Major > Fix For: 5.0-beta > > > Given `kylin.job.max-concurrent-jobs=0`, the initialization of job scheduler > encounters NPE. -- This message was sent by Atlassian Jira (v8.20.10#820010)