Change Server Mode from Dedicated to Shared.

How can find in which mode database is running ?


1. If "SHARED_SERVERS" parameter value is "0". then database running on dedicated server mode.
2. select username,status,server from v$session;
Here SERVER column give server mode 1. dedicated or 2. Shared
3. LISTNER.LOG file
04-SEP-2007 18:46:10 * (CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=ORCL)


We have to configure two parameters for change server mode from Dedicated to Shared.
SHARED_SERVERS & DISPATCHERS parameters.

------------------------------------------------------------
SQL>show parameter shared_servers
NAME VALUE TYPE
----------------------------------------------
shared_servers integer 0

SQL> alter system set shared_servers = 1;
System altered.

SQL>show parameter shared_servers
NAME VALUE TYPE
----------------------------------------------
shared_servers integer 1


SQL>show parameter dispatchers
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------dispatchers string (PROTOCOL=TCP)
max_dispatchers integer

SQL> alter system set dispatchers = "(PROTOCOL=TCP) (DISPATCHERS=1) (SERVICE=ORCL1)";
System altered.

or you can edit tnsnames.ora file like
ORCL1 =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.100.64)(PORT = 1521)) (CONNECT_DATA =
(SERVICE_NAME = orcl1)
(SERVER=SHARED)
)
)
Note : For Backward compatibility, if shared_server is not included in init parameter file or dispatchers is included and it specify aleast 1 dispatcher. then shared_server mode is enable.
but if not shared_server or nor dispatcher specified in init parameter file . then you have to set shared_server parameter aleast greater than 0 for enable shared server mode.

If We set only shared_server parameter but dispatchers parameters is not set then oracle server automatically create one dispatcher for shared server.

dispatchers string (PROTOCOL=TCP)