when i build the cube,the step create htable failed,the error message below,why the reason org.apache.kylin.engine.mr.exception.HadoopShellException: java.lang.NullPointerException at org.apache.kylin.engine.mr.common.CubeStatsReader.getCuboidSizeMapFromRowCount(CubeStatsReader.java:227) at org.apache.kylin.engine.mr.common.CubeStatsReader.getCuboidSizeMap(CubeStatsReader.java:180) at org.apache.kylin.engine.mr.common.CubeStatsReader.getCuboidSizeMap(CubeStatsReader.java:176) at org.apache.kylin.storage.hbase.steps.CreateHTableJob.run(CreateHTableJob.java:100) at org.apache.kylin.engine.mr.MRUtil.runMRJob(MRUtil.java:93) at org.apache.kylin.engine.mr.common.HadoopShellExecutable.doWork(HadoopShellExecutable.java:63) at org.apache.kylin.job.execution.AbstractExecutable.execute(AbstractExecutable.java:179) at org.apache.kylin.job.execution.DefaultChainedExecutable.doWork(DefaultChainedExecutable.java:71) at org.apache.kylin.job.execution.AbstractExecutable.execute(AbstractExecutable.java:179) at org.apache.kylin.job.impl.threadpool.DefaultScheduler$JobRunner.run(DefaultScheduler.java:113) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:748) result code:2 at org.apache.kylin.engine.mr.common.HadoopShellExecutable.doWork(HadoopShellExecutable.java:73) at org.apache.kylin.job.execution.AbstractExecutable.execute(AbstractExecutable.java:179) at org.apache.kylin.job.execution.DefaultChainedExecutable.doWork(DefaultChainedExecutable.java:71) at org.apache.kylin.job.execution.AbstractExecutable.execute(AbstractExecutable.java:179) at org.apache.kylin.job.impl.threadpool.DefaultScheduler$JobRunner.run(DefaultScheduler.java:113) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:748)