PgAgent daemon terminated itself when it was running a time-consuming job.

My environment is Ubuntu 16.04 LTS, Postgres 9.6.8 with PgAgent 4.0 installed and setup successfully. 

I tried to use a PgAgent Job to pull data from a MySQL table using FDW on a routine basis in order to keep a updated copy of the mysql table. This job has two steps. When I run those steps directly, the first one would take less than 30 mins and the second one usually takes 44 minutes. However, when I try to run it with PgAgent, my logs showed me that only the first step was finished, and PgAgent daemon was terminated during this job and it would never execute the second step.  

Is there a solution on this issue? If it is beyond the capability of PgAgent, what solution would help me? the system cron? I really like the feature of PgAgent that steps could be executed one by one if the previous is done, so I would hope I could just set up some configuration and get this fixed. 

Thank you.