usser_session_program1.htm
Session information: V$SESSION in SQL query scripts, displays information for each current session.

select username, to_char(logon_time,'DD-MM-YY HH:MI:SS') AS TIME, program FROM v$session where username ='SCOTT'
Using custom oracle-php-tool
In the above example, we force-formatted , over the default date type. At this point we have a trigger that acts with oci_pconnect, which stays open and the phpscript reuses the chached database connection. 

In persistent connection , when php process terminates the connection cache is destroyed and database connection is closed.

I am not yet sure the advantage of PERSISTENT  connection with php script. In apache server would shut down to close the persistent connection.