For the high-level view, you can directly use the SNP_SESSION table in your workrepository.
SELECT * FROM SNP_SESSION s ORDER BY SESS_BEG DESC
The column SESS_DUR gives you the execution time and column SESS_STATUS tells you if it was successful or finished with error.
Here are the status code :
'E' : Error
'D' : Done
'W' : Waiting
'M' : Warning
'R' : Running
'Q' : Queued (not sure about this one).
You will also find the error message (if any), the context used, the agent used, ...
Hope it helps.