The checkpoint duration includes the processes of barrier alignment and state snapshot. Every task has to receive all the barriers from all the channels, then trriger to snapshot state. I guess the barrier alignment may take long time for your case, and it is specially critical during backpressure. You can check the metric of "checkpointAlignmentTime" for confirmation.
Best, Zhijiang ------------------------------------------------------------------ 发件人：徐涛 <happydexu...@gmail.com> 发送时间：2018年10月10日(星期三) 13:13 收件人：user <user@flink.apache.org> 主 题：Small checkpoint data takes too much time Hi I recently encounter a problem in production. I found checkpoint takes too much time, although it doesn`t affect the job execution. I am using FsStateBackend, writing the data to a HDFS checkpointDataUri, and asynchronousSnapshots, I print the metric data “lastCheckpointDuration” and “lastCheckpointSize”. It shows the “lastCheckpointSize” is about 80KB, but the “lastCheckpointDuration” is about 160s! Because checkpoint data is small , I think it should not take that long time. I do not know why and which condition may influent the checkpoint time. Does anyone has encounter such problem? Thanks a lot. Best Henry
