All message types issued by a program running in the background are stored in a job log, which you can display either to obtain information on a prematurely terminated program or to complete a detailed investigation of a particular background processing run. A separate log file is created for each job.
Deleting Log Files
You should never delete log files directly. If you want to clear the log directory, you must delete the jobs to which the logs belong. In the process, the logs are also deleted.
Job logs are held in the TemSe temporary sequential objects storage facility. TemSe is configured to always store job logs as operating system files in the shared SAP directories. If you delete log files directly at the operating system level, you create inconsistencies in the TemSe database, which you'll then need to eliminate with the Consistency check function in Transaction SP12.
Log Messages
Log messages are generally output using ABAP keyword MESSAGE. With the exception of ABAP breakpoint statistics, no other data is normally output to the job log.
ABAP Short Dumps
If an ABAP program generated a dump when it terminated abnormally, you can display the dump by clicking on the Abend message.
Batch Input Messages
Messages output during batch input sessions are not recorded in the job log. These messages are output only to the batch input system.