Process vs Sessions parameter values in Oracle

~ Process vs Sessions parameter values in Oracle
~ Setting Sessions and Transaction parameter values in Oracle 11g with respect to process parameter values.
~ Applicable to different oracle version as described.

-- Formula ( upto Oracle version 11.2.0.x.x) - I believe

processes=x
sessions=x*1.1+5
transactions=sessions*1.1
Click Here to view from Oracle document
-- To View all
$sqlplus '/as sysdba'
sql> show parameter sessions;
sql> show parameter processes;
sql> show parameter transactions;

-- To set ( as per as usual process)

alter system set processes=1000 scope=spfile;
alter system set sessions=1105 scope=spfile;
alter system set transactions=1216 scope=spfile;

See Document: http://docs.oracle.com/cd/B28359_01/server.111/b28320/initparams220.htm

-- In Oracle 11.2.0.3.x onwards

-- Deviation ( as I observed, Concluded formula) - May be a bug
-- When I set process values and bounce the database automatically values set for sessions and transactions

In 11.2.0.3 formula is :

sessions=(No_of_processes*1.5)+26

i.e.,
processes=x
sessions=x*1.5+26
transactions=sessions*1.1

Example:
If process=500, the sessions will be 776, Transactions will be 853.

-- When viewed from one of production database environment:

SQL> show parameter process;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
aq_tm_processes                      integer     1
cell_offload_processing              boolean     TRUE
db_writer_processes                  integer     1
gcs_server_processes                 integer     0
global_txn_processes                 integer     1
job_queue_processes                  integer     1000
log_archive_max_processes            integer     4
processes                            integer     500
processor_group_name                 string
SQL> show parameter session;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
java_max_sessionspace_size           integer     0
java_soft_sessionspace_limit         integer     0
license_max_sessions                 integer     0
license_sessions_warning             integer     0
session_cached_cursors               integer     50
session_max_open_files               integer     10
sessions                             integer     776
shared_server_sessions               integer
SQL> show parameter transaction;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
transactions                         integer     853
transactions_per_rollback_segment    integer     5

* Some sites also explains similar issues / bugs. Please go through the below link. But I have little bit deviations.

http://hoopercharles.wordpress.com/2012/02/08/sessions-derived-value-formula-doc-bug-explains/

Note: When spfile is common location ( in asm) in RAC database, then do in mount stage and bounce the instances.

Thanks