I created the database using DBCA which means SPFILE is created by default and database is started using SPFILE. Later i made some change to 'processes' parameter dynamically and created PFILE from SPFILE.
Now when i look at PFILE, i can't see 'SESSIONS' Parameter..but when i issue 'show parameter sessions' it says Sessions as 720. I need to edit this parameter also why can't i see this parameter in PFILE ?
The parameter SESSIONS is derived & static parameter and its default value is (1.1 * PROCESSES) + 5. If you want to change its value then you need to add it in pfile and start the database using this pfile and then recreate spfile from pfile.