Problem: ORA-12523: TNS:listener could not find instance appropriate for the client connection
I have been tried to connect my DB (SID=WDH) by command: sqlplus system/system@dwh
after that, it orccured error so I COULDN’T resovle problem. System has a message “ORA-12523: TNS:listener could not find instance appropriate for the client connection”. Please help me solve this matter.
====
another information:
————-
My PC has been installed ORACLE9i on C partion with Path C:Oracle
And also, i has been installed ORACLE FORM10g.
————-
I think my PC will conflit with TNSNAME or connection in SQLNET.ORA file. I’ll show you about information of my TNSNAME.ORA; SQLNET.ORA file of ORACLE 9i and ORACLE FORM 10g
————————
9i
——————
TNSNAME.ORA
+++++++++++++++++++++++++++++++
WDH =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = nghiemnd)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = WDH)
)
)
+++++++++++++++++++++++++++++++
SQLNET.ORA
+++++++++++++++++++++++++++++++
# SQLNET.ORA Network Configuration File: C:oracleora92networkadminsqlnet.ora
# Generated by Oracle configuration tools.
SQLNET.AUTHENTICATION_SERVICES= (NONE)
# This file is actually generated by netca. But if customers choose to
# install “Software Only”, this file wont exist and without the native
# authentication, they will not be able to connect to the database on NT.
NAMES.DIRECTORY_PATH= (TNSNAMES, ONAMES, HOSTNAME)
———————————————————–
ORACLE FORM 10g (has been installed on J partition with name J:DevSuiteHome_2)
———————————————————–
TNSNAME.ORA
++++++++++++++++++++++++++++++++
WDH =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = nghiemnd)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = WDH)
)
)
++++++++++++++++++++++++++++++++
SQLNET.ORA
++++++++++++++++++++++++++++++++
# sqlnet.ora Network Configuration File: J:DevSuiteHome_2networkadminsqlnet.ora
# Generated by Oracle configuration tools.
SQLNET.AUTHENTICATION_SERVICES = (NONE)
NAMES.DIRECTORY_PATH= (TNSNAMES, ONAMES, HOSTNAME)
+++++++++++++++++++++++++++++++++++
Solution: ORA-12523: TNS:listener could not find instance appropriate for the client connection
1. See LISTENER.ORA file for entry of your DB
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = D:Ora10g)
(PROGRAM = extproc)
)
(SID_DESC =
(SID_NAME = test)
(ORACLE_HOME = D:Ora10g)
)
)
2. Set in the environment variables
ORACLE_SID ——> WDH
3. Make Oracle default home the home of the 9i instance.
4. Restart the listener:
c:>lsnrctl stop
c:>lsnctl start
5. What is the result of
C:>tnsping WDH
6. Try to connect from the box of the Oracle instance:
SQL>connect / as sysdba
What is the result?
7. Speak with the sysadmin. Possibly there is another computer with the same name!
(SID_DESC =
(SID_NAME = test)
(ORACLE_HOME = D:Ora10g)
)
