10g stopped working after 11g installed. Getting ORA-12514: error

Question

I had Oracle 10g installed in win2000 sp2. with port 1521.
I have installed Oracle 11g on the same system. with port 1522.
I am able to start both the instances and tnslistener but I am not able to connect to Oracle10g database. Getting following error.
ORA-12514: TNS:listener does not currently know of service requested in connect
descriptor
I have done the following check.
c:\> tnsping tek10g
TNS Ping Utility for 32-bit Windows: Version 11.1.0.6.0 - Production on 14-MAR-2
008 13:04:26
Copyright (c) 1997, 2007, Oracle. All rights reserved.
Used parameter files:
C:\app\mmurugai\product\11.1.0\db_1\network\admin\sqlnet.ora
Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)
(HOST = PC456)(PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME = tek10g) (SRVR = DE
DICATED)))
OK (50 msec)
2) Checked lsnrctl services
LSNRCTL> services
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=PC456.SYNTELORG.COM)(PO
T=1522)))
Services Summary...
Service "orcl11g" has 1 instance(s).
Instance "orcl11g", status READY, has 1 handler(s) for this service...
Handler(s):
"DEDICATED" established:3 refused:0 state:ready
LOCAL SERVER
Service "orcl11gXDB" has 1 instance(s).
Instance "orcl11g", status READY, has 1 handler(s) for this service...
Handler(s):
"D000" established:0 refused:0 current:0 max:1022 state:ready
DISPATCHER <machine: PC456, pid: 284>
(ADDRESS=(PROTOCOL=tcp)(HOST=PC456.SYNTELORG.COM)(PORT=2963))
Service "orcl11g_XPT" has 1 instance(s).
Instance "orcl11g", status READY, has 1 handler(s) for this service...
Handler(s):
"DEDICATED" established:3 refused:0 state:ready
LOCAL SERVER
The command completed successfully
LSNRCTL>
I am not able to see my tek10g 10g database details.
I also checked my tnsnames.ora file which has the entries properly.
Sqlnet.ora file has
SQLNET.AUTHENTICATION_SERVICES= (NTS)
NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)
How to solve this issue? Is that possible to run oracle 10g and oracle 11g in same host?
Thanks in Advance...
regards,
Manikandan

Answer 1

The approach I would take, in general is:
1) pick a listener, and only one. Get that working.
2) Make sure all the databases register to that listener
3) Fix the TNSNAMES.ORA files appropriately.
To fix the listener
1) Verify the listener address matches the current environment
SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = C:\oracle\app\oracle\product\10.2.0\server)
      (PROGRAM = extproc)
    (SID_DESC =
      (SID_NAME = CLRExtProc)
      (ORACLE_HOME = C:\oracle\app\oracle\product\10.2.0\server)     << - MUST point to correct HOME
      (PROGRAM = extproc)
LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC_FOR_XE))
      (ADDRESS = (PROTOCOL = TCP)(HOST = myHOST)(PORT = myPORT))
  )where
myHOST is this host's resolvable name or IP address
myPORT is the port (default 1521) that the listener should monitor
The HOST is often a problem if the machine uses DHCP.
2) Register the databases
On startup, database will auto-register to the listener defined in the init parameter 'LOCAL_LISTENER', which defaults to 'HOST={current_host}, PORT=1521'
After startup, if the listener is taken down, you can register each database manually using the DBA command
ALTER SYSTEM REGISTER;
Either way, it should show up in the output of 'lsnrctl status'
While you are accessing the database, you might want to find out which services the database supports. That can be done in SQLPlus using the command
SHOW PARAMETER SERVICE_NAMES
Note that the database name is the default service name.
3) Fix [all] the TNSNAMES.ORA file[s].
Each SERVICE_NAME from the previous list that you want to access from this client, yu should find an entry that looks like
myTEST =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = myHOST)(PORT = myPORT))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = mySERVICE)
myTEST is the alias I want to look up by using it as the connect target string.
myHOST should match the HOST= entry in the LISTENER.ORA
myPORT MUST match the PORT= entry in the LISTENER.ORA
mySERVICE is the Service to which I am asking the listener to connect me, as found in the lsnrctl status output