Service names for db. instance.

Question

When I display status for listener
I can see two services for one instance,
but when I select service_names from v$parameter view
there is just one there. Can someone tell me how is it possible?
Thanks for advice,
M.

Answer 1

Not sure to understand you. Do you mean that this entry
Service "db102" has 1 instance(s).
  Instance "db102", status READY, has 2 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:0 refused:0 state:ready
         LOCAL SERVER
      "D000" established:0 refused:0 current:0 max:972 state:ready
         DISPATCHER <machine: Feynman, pid: 29127>
         (ADDRESS=(PROTOCOL=tcp)(HOST=localhost)(PORT=49536))shouldn't be there ? Well, actually the behaviour is different from 10.1 (and 9i) :
SYS@test10 SQL> show parameter service_names
NAME                                 TYPE        VALUE
service_names                        string      a.world
SYS@test10 SQL> show parameter dispatchers
NAME                                 TYPE        VALUE
dispatchers                          string      (PROTOCOL=TCP)
max_dispatchers                      integer     3
SYS@test10 SQL> !lsnrctl services
LSNRCTL for Linux: Version 10.1.0.3.0 - Production on 30-JUN-2006 18:32:11
Copyright (c) 1991, 2004, Oracle.  All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=localhost)(PORT=1521)))
Services Summary...
Service "PLSExtProc" has 1 instance(s).
  Instance "PLSExtProc", status UNKNOWN, has 1 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:0 refused:0
         LOCAL SERVER
Service "a.world" has 1 instance(s).
  Instance "test10", status READY, has 2 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:0 refused:0 state:ready
         LOCAL SERVER
      "D000" established:0 refused:0 current:0 max:972 state:ready
         DISPATCHER <machine: Feynman, pid: 11009>
         (ADDRESS=(PROTOCOL=tcp)(HOST=localhost)(PORT=36538))
The command completed successfully
SYS@test10 SQL>                                                                                                      In 10.2 a service = db name is always present, even with SERVICE_NAMES = null string :
SYS@db102 SQL> alter system set service_names = '';
System altered.
SYS@db102 SQL> !lsnrctl services
LSNRCTL for Linux: Version 10.2.0.1.0 - Production on 30-JUN-2006 18:37:44
Copyright (c) 1991, 2005, Oracle.  All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=localhost)(PORT=1521)))
Services Summary...
Service "db102" has 1 instance(s).
  Instance "db102", status READY, has 2 handler(s) for this service...
    Handler(s):
      "D000" established:0 refused:0 current:0 max:972 state:ready
         DISPATCHER <machine: Feynman, pid: 11171>
         (ADDRESS=(PROTOCOL=tcp)(HOST=localhost)(PORT=36677))
      "DEDICATED" established:0 refused:0 state:ready
         LOCAL SERVER
The command completed successfully
SYS@db102 SQL>                                                                                       Maybe this guarantees db service registration in any situation...