Why Is not an Application Displayed When I Run the Application with the Empty Part File?

Question

When I run an application with an empty part file in HDFS with the log grouping function enabled, why is not the application displayed on the homepage of JobHistory?

Answer

On the JobHistory page, information about applications is updated only with changed sizes of part files in HDFS. If a file is read for the first time, its size is compared with 0. The file is read only when the file size is greater than 0.

When the log grouping function is enabled, if the application you run does not have jobs in running status, the part file is empty. As a result, JobHistory does not read the part file and the application information is not displayed on the JobHistory page. However, if the size of part file is changed later, the application will be displayed on JobHistory.