Home
All Oracle Error Codes
Oracle DBA Forum

Frequent Oracle Errors

TNS:could not resolve the connect identifier specified
Backtrace message unwound by exceptions
invalid identifier
PL/SQL compilation error
internal error
missing expression
table or view does not exist
end-of-file on communication channel
TNS:listener unknown in connect descriptor
insufficient privileges
PL/SQL: numeric or value error string
TNS:protocol adapter error
ORACLE not available
target host or object does not exist
invalid number
unable to allocate string bytes of shared memory
resource busy and acquire with NOWAIT specified
error occurred at recursive SQL level string
ORACLE initialization or shutdown in progress
archiver error. Connect internal only, until freed
snapshot too old
unable to extend temp segment by string in tablespace
Credential retrieval failed
missing or invalid option
invalid username/password; logon denied
unable to create INITIAL extent for segment
out of process memory when trying to allocate string bytes
shared memory realm does not exist
cannot insert NULL
TNS:unable to connect to destination
remote database not found ora-02019
exception encountered: core dump
inconsistent datatypes
no data found
TNS:operation timed out
PL/SQL: could not find program
existing state of packages has been discarded
maximum number of processes exceeded
error signaled in parallel query server
ORACLE instance terminated. Disconnection forced
TNS:packet writer failure
see ORA-12699
missing right parenthesis
name is already used by an existing object
cannot identify/lock data file
invalid file operation
quoted string not properly terminated

Re: TNS Resolution

Mladen Gogala

2006-01-18

Replies:

On 01/18/2006 10:50:53 AM, Jonathan Knight wrote:
> I have a strange (to me anyway) problem with TNS.

The problem is not strange. It is a configuration problem.

>
> Connecting with SQL*Plus, SQL*Navigator, TOAD: I get
> "ORA-12154: TNS:could not resolve service name"

You should kiss the toad and fix your tnsnames.ora

>
> But, tnsping returns in 100-130 msecs. ?!?!?!

The tnsping contacts the listener. If the listener is there, TNSPING is
successful. Service name, on the other hand, is a property of an
instance, not listener.


>
> I'm confused. Any thoughts?


Jonathan, your TNS descriptor should look something like this:
O10G =
 (DESCRIPTION =
  (ADDRESS_LIST =
    (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
  )
  (CONNECT_DATA =
    (SERVICE_NAME = oracle)
    (SEVER = DEDICATED)
  )
 )

To be able to connect, your database must have service name defined like this:
SQL> show parameter service_names

NAME                      TYPE     VALUE
------------------------------------ ----------- ------------------------------
service_names                string    oracle
SQL>

Your problem is that the database doesn't have the same service name
as your tnsnames.ora. What you need to do is either to change SERVICE_NAME
into SID and then put the appropriate SID or set SERVICE_NAME to the value
exported by the instance. If your database isn't RAC, in which case several
instances may have the same value for the service_name both methods are
equivalent. From the aesthetic point of view service name is strongly
preferred, at least by me.


--
Mladen Gogala
http://www.mgogala.com
--
http://www.freelists.org/webpage/oracle-l