====== Oracle Prcoess Vs Session ======

  * The parameters SESSIONS and PROCESSES determine the size of two arrays in the SGA.

  * If you try to create more sessions on an instance than specified \\ by the SESSIONS  parameter, you will get an ORA-00018: maximum \\ number of sessions exceeded.

  * If you try to create more processes on an instances than specified by the PROCESSES prameter, \\ you wil get an ORA-00020: maximum number of processes exceeded.

  * The number of sessions and processes on your instance can been seen using a COUNT(*) against V$PROCESS and V$SESSION.
Your job is to determine resonable values, so your users can continue to work without getting neither ORA-18 nor ORA-20 during normal conditions. \\ (A run away job, that keeps starting new sessions is not a normal condition, and it should be stopped by ORA-18 or ORA-20 whichever happens first).

  * You can join the two V$-views using the columns V$SESSION.PADDR and V$PROCESS.ADDR.

  * It is quite normal to see a 1:1 relationship between processes and sessions. \\ However one OCI-program can create multiple sessions belonging to one process. \\ Users of Oracle Portal will experience this behaviour.

  * The default value for SESSIONS is **1.1*PROCESSES + 5**. \\ It is appropriate for some databases and inappropriate for others (e.g. Oracle Portal).

> Also, I remember a limit on the OS regarding the number of processes
> allowed per Oracle user - also I know there is a semaphore 
> relationship.

  * On HP-UX there is a kernel parameter called NPROC. \\ Like PROCESSES and SESSIONS it should have a reasonable value.