3) What is session_start_timestamp tracking? In other words what does it match up to here: ans: This is the format to timestamp=%m,user=%u,db=%d,app=%a,client=%h,transaction-ID=%x,session_start_timestamp=%s,SQL_state=%e The time when the session is session_started _start_timestamp
4) What is the process that started 2018-04-26 10:08:19?
ans: Its an backed process of Postgre started parallel worker
5) The query in the log started at 2018-05-07 00:32:46, what is it doing? ans : query running from an agent if any processing is going on the front end some of the query will run
So there is process that opens a connection, leaves it open and then periodically runs queries?