Ошибка ora 12514 tns listener does not currently know of service requested in connect descriptor

Are you getting an “ORA-12514: TNS:listener does not currently know or service requested in connect descriptor” error? Learn what causes it and how to resolve it in this error.

If you try to connect to an Oracle database, you may receive this error:

ORA-12514: TNS:listener does not currently know or service requested in connect descriptor

This error means that a listener on the Oracle database has received a request to establish a connection. However, the connection descriptor mentions a service name that has not been registered with the listener, or has not been configured for the listener.

ORA-12514 Solution

There are a few steps to resolve this error.

1. Check the service names on the database (if possible)
2. Update TNSNAMES.ORA to include the service name

Step 1: Check the service names on the database

The first step to resolve the ORA-12514 is to see which service names the database knows about.

If you’re able to connect to your database, run the following query:

SELECT value
FROM v$parameter
WHERE name = 'service_names';

VALUE

XE

This will show all of the service names your database knows about.

You’ll need to add these into the TNSNAMES.ORA file, which I’ll show you how to do shortly.

What if you can’t connect to your database? This is a valid question, seeing as you’re getting this error when you try to connect to the database.

You could use a different connection string.

Or, you could connect to the server and run sqlplus locally.

Or, you could ask a coworker or a DBA to run this command for you.

This all depends on how your environment is set up.

While you’re here, if you want an easy-to-use list of the main features in Oracle SQL, get my SQL Cheat Sheet here:

Alternative: check which service names are known by the listener

Another way of seeing which service names are available to the listener is by running the lsnrctl command

lsnrctl services

This will show you the names of the services, which you can check against your connect descriptor. It’s an alternative way to getting the service names if you can’t connect to the database as mentioned in the previous step.

Step 2: Update your TNSNAMES.ORA file

After you have the name of the service, open your TNSNAMES.ORA file.

This file is located here:

%ORACLE_HOME%NETWORKADMIN

ORACLE_HOME is where your Oracle database is installed on the server, or on your own computer if you’re using Oracle Express.

For example, in my installed version of Oracle Express, my ORACLE_HOME is:

C:oraclexeapporacleproduct11.2.0server

So, my TNSNAMES is located here:

C:oraclexeapporacleproduct11.2.0servernetworkadmin

Your TNSNAMES.ORA file has one or more entries in it that represent your databases. They are in the following format:

<addressname> =
(DESCRIPTION =
  (ADDRESS_LIST =
  (ADDRESS = (PROTOCOL = TCP)(Host = <hostname>)(Port = <port>))
  )
(CONNECT_DATA =
  (SERVICE_NAME = <service_name>)
)
)

The addressname is what you use in the connection string, and service_name is what the service is known as on the database (from step 1)

Now, update the TNSNAMES.ORA by either adding a new entry or modifying an existing entry. You need to make sure that there is an entry that has a service_name value that is equal to the value you found in step 1.

XE =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = Ben-PC)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = XE)
    )
  )

Once you have done this, you should be able to connect to your database in the method you wanted to that caused this error.

sqlplus [email protected]

This should now work.

So, that’s how you resolve the ORA-12514 error.

You can read my guide to the Oracle errors here to find out how to resolve all of the Oracle errors.

While you’re here, if you want an easy-to-use list of the main features in Oracle SQL, get my SQL Cheat Sheet here:

Ошибка TNS-12514 может возникнуть во множестве случаев, как на windows, так и на unix/linux платформах. Но чаще всего неприятности с подключением происходят именно на windows платформе.

Первое, что необходимо проверить, настройки самого прослушивателя listener.ora:

LISTENER =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
    (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
  )

ADR_BASE_LISTENER = C:apporacleproduct12.1.0dbhome_1

Далее следует убедиться, что экземпляр БД запущен.

> export ORACLE_SID=my_sid
> sqlplus / as sysdba

Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options

SQL>

Если вместо версии БД мы получаем сообщение:

Connected to an idle instance.

SQL>

то запускаем БД:

SQL>startup

Если подключиться к БД по-прежнему не удается, то проверяем процесс прослушивателя.

LSNRCTL for 64-bit Windows: Version 12.1.0.2.0 - Production on 14-DEC-2015 16:50:50

Copyright (c) 1991, 2014, Oracle.  All rights reserved.

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=localhost)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for 64-bit Windows: Version 12.1.0.2.0 - Production
Start Date                14-DEC-2015 16:37:40
Uptime                    0 days 0 hr. 13 min. 10 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   C:apporacleproduct12.1.0dbhome_1listener.ora
Listener Log File         C:apporacleproduct12.1.0dbhome_1logdiagtnslsnrphoenixlisteneralertlog.xml
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=localhost)(PORT=1521)))
  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1521)))
The listener supports no services
The command completed successfully

Обычно каждая БД регистрируется автоматически. Если появляется сообщение “прослушиватель не поддерживает сервисов”, то, как правило, экземпляр БД не может зарегистрироваться. При регистрации используются сетевые параметры, заданные по-умолчанию. Если они не совпадают с настройками прослушивателя, то в БД необходимо установить параметр LOCAL_LISTENER. По-умолчанию параметр имеет пустое значение.

SQL> show parameter local_listener;

NAME                                 TYPE        VALUE
------------------------------------ ----------- -------------------------------
local_listener                       string

SQL> alter system set LOCAL_LISTENER='(ADDRESS = (PROTOCOL=TCP)(HOST=localhost)(PORT=1521))' scope=both;

System altered.

SQL> show parameter local_listener;

NAME                                 TYPE        VALUE
------------------------------------ ----------- -------------------------------
local_listener                       string      (ADDRESS = (PROTOCOL=TCP)(HOST=
                                                 =localhost)(PORT=1521))
SQL>

После установки параметра БД автоматически регистрируется для прослушивателя.

ORA-12514 means that the listener cannot find any matched service with yours, so it cannot establish the connection with the database for you. As a result, it responds ORA-12514 to alert the failed connection.

As a DBA, I have seen several kinds of ORA-12514 in different scenarios and solved them by different means. Here I divide scenarios that could throw ORA-12514 into several error patterns as below:

1. Common Situations
2. Restarting a Database
3. Switching over to Standby
4. Using a Database Link

Only one thing that can be sure in ORA-12514 is that the target listener is up and running. That is to say, the listener is reachable.

For unknown requested SID, the listener throws ORA-12505: TNS:listener does not currently know of SID given in connect. It may have different error patterns from this post.

ORA-12514 in Common Situations

Let’s see how we get ORA-12514. First of all, we have to make sure the listener on the database server is reachable by using tnsping.

C:Usersed>tnsping ora11g

TNS Ping Utility for 64-bit Windows: Version 12.1.0.1.0 - Production on 22-JUL-2014 19:24:04

Copyright (c) 1997, 2013, Oracle.  All rights reserved.

Used parameter files:
C:oracleappclientedproduct12.1.0client_1networkadminsqlnet.ora

Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = oracle-11g-server)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = ORCL)))
OK (60 msec)

OK, the remote listener is up and reachable. Please note that, the message of successful tnsping did not indicate that the service name is existing on the remote listener.

Next, we test the connection to the database by sqlplus (SQL*Plus).

C:Usersed>sqlplus hr/hr@ora11g
...
ERROR:
ORA-12514: TNS:listener does not currently know of service requested in connect
descriptor

Enter user-name:

Cause

When the connection came, the listener found no matched service name registered with it. Consequently, the listener had no idea which database should be used to service the connection. Here are some possible causes of ORA-12514:

1. No instance

The database was not available or say idle, no any dynamic services registered with the listener. That’s why we saw ORA-12514.

2. Mismatched service name

The service name of the connect descriptor in tnsnames.ora did not match the service name in the listener. That is to say, the listener does not currently know of service requested in connect descriptor.

3. Not registered

If the database instance is up and running, the service name may not registered with the listener at specific port as you thought. By default, the service port of listener is 1521. But sometimes, it could switch to another port, say 1522.

Please note that, ORA-12514 is an error threw by the listener specifically for the client side. The database is no way to know such problem.

Solutions

The solutions to ORA-12514 are to make sure the following things:

1. The database is available

If there’s no instance, then no service name will register with the listener. You should startup the instance, then LREG will automatically register the service in 60 seconds.

If you are sure that the database is up and running and still got ORA-12514, things may be complicated. Let’s keep looking for other solutions.

2. The service names are matched

The service name in the connect descriptor of client’s tnsnames.ora shall match the service registered in the listener. Sometimes, it’s just a typo problem.

In short, the service names in the following 3 parties should be matched with each other in order to solve ORA-12514.

• Connect descriptor.
• The listener.
• The database.

We talk about them respectively below.

Connect Descriptor

Let’s see an example of connect identifier. In which, the body is a connect descriptor.

[oracle@test ~]$ vi $ORACLE_HOME/network/admin/tnsnames.ora
...
ORCL =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = oracle-11g-server)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = ORCL)
    )
  )

The question is, where is tnsnames.ora?

The Listener

The connect descriptor is easily checked, but how do we check the service names of the listener? See the following command:

[oracle@test ~]$ lsnrctl status
...
Services Summary...
Service "ORCL" has 1 instance(s).
  Instance "ORCL", status READY, has 1 handler(s) for this service...

For a specific listener name, you should do this:

[oracle@test ~]$ lsnrctl status <listener_name>

The Database

If there’s no matched service name in the listener, we should check the service names of the instance by OS authentication. No credentials are needed.

[oracle@test ~]$ sqlplus / as sysdba
...
SQL> show parameter service_names

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
service_names                        string      ORCL

In case that you have no way to query the database, you can make a guess. Usually but not always, the service name is the same as the database unique name (DB_UNIQUE_NAME). The database unique name is the same as the instance name ($ORACLE_SID) for a single-instance database.

If both service names in the client and database are matched, but the listener showed a different service name or «The listener supports no services». The database may register a different listener, let’s keep reading this post.

3. The host and port are both right

Sometime, we may go for the wrong destination of the listener, either host or port was incorrect. As a result, we saw ORA-12514 because there’s no matched service name with that listener. We should check the host and port in the connect descriptor of the TNS name.

Chances are, the correct hostname may be resolved as the wrong IP address by DNS. Consequently, connections took us to the wrong database server. This could happen when we switched from an old machine to a new database server. So we should focus on name resolution problem first.

For those ORA-12514 caused by name resolution, we can use the IP address instead of hostname to connect the database for clients to work around it. Additionally, DBA should also check both values of HOST and PORT in listener.ora.

During the troubleshooting on the name resolution, you might see TNS-12545: Connect failed because target host or object does not exist temporarily.

4. Instance registers it services with the right listener

The instance may register with the another listener which services whatever port other than 1521. Consequently, no service name is supported by that listener.

That’s why we always see ORA-12514 only in clients or TNS-12514 in the listener’s log, the database instance will never know such problem.

Now we have a question: What listener is the instance using? If the database is using a different listener other than the default one, we can check a parameter named LOCAL_LISTENER for sure:

SQL> show parameter local_listener

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
local_listener                       string      (ADDRESS=(PROTOCOL=TCP)(HOST=o
                                                 racle-11g-server)(PORT=1522))

If the default listener at port 1521 in the same machine is used, the value could be empty. Otherwise, we will see the listener description like the above.

In a very rare case, the database uses a remote listener to register its service names. This is what Class of Secure Transports (COST) fights against.

For more troubleshooting beside ORA-12514, you may refer to Oracle 18c Net Services Administrator’s Guide: 15 Testing Connections.

ORA-12514 When Restart a Database

It’s pretty easy to explain why you got ORA-12514 when you restart a database. Please compare the following two cases.

Connect to the database through listener

[oracle@test ~]$ sqlplus /nolog
...
SQL> conn sys@orcl as sysdba
Enter password:
Connected.
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup;
ORA-12514: TNS:listener does not currently know of service requested in connect descriptor

We saw ORA-12514 after we tried to startup the stopped database. Here is the reason: When you shutdown the instance, you lost the connection from the database and the service was unregistered from the listener, no more service information of the database on the listener. Therefore, ORA-12514 notified that you can’t do any further to this database in this way.

To solve ORA-12514 thoroughly, you should add a static service registration to the listener for your database. Otherwise, you have to connect to the database by OS authentication.

Let’s see how to avoid ORA-12514 if you are going to do critical jobs like shutdown or startup database through OS authentication.

Connect to the database through OS authentication

You don’t have to provide the password through OS authentication.

[oracle@test ~]$ sqlplus /nolog
...
SQL> conn / as sysdba
Connected.
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup;
ORACLE instance started.

Total System Global Area 1553305600 bytes
Fixed Size                  2253544 bytes
Variable Size             956304664 bytes
Database Buffers          587202560 bytes
Redo Buffers                7544832 bytes
Database mounted.
Database opened.

Can you tell the difference? By this method, you can never lose your connection during down time no matter the listener is up or not. No ORA-12514 interrupts you.

By the way, I talked about how to connecting an idle, NOMOUNT or RESTRICT database from remote clients in another post. It may help you to clarify some concepts about ORA-12514.

ORA-12514 When Switchover to Standby

DGMGRL> switchover to standby;
Performing switchover NOW, please wait...
Operation requires a connection to instance "primary" on database "standby"
Connecting to instance "primary"...
Connected.
New primary database "standby" is opening...
Operation requires startup of instance "primary" on database "primary"
Starting instance "primary"...
Unable to connect to database
ORA-12514: TNS:listener does not currently know of service requested in connect descriptor

Failed.
Warning: You are no longer connected to ORACLE.

This kind of error pattern of ORA-12514 is the most confusing, because you might have no idea what’s going on according to the last message «Failed» in console. This is what’s going on:

1. The former standby is up and now playing the primary role.
2. The former primary is down and going to play the standby role, but the data guard broker is unable to mount the instance due to the lost contact. As a result, we saw ORA-12514 in DGMGRL.

That is to say, the switchover is incomplete, but it does not mean a failure. This is because the former primary database is down and the broker lost the contact that caused ORA-12514.

Here are the actions that you have to take in order to complete the switchover. Please start up and mount the former «primary» database manually. After that, the data guard will automatically synchronize the data so as to complete the switchover.

The preventive action to ORA-12514 in an incomplete switchover is to add a very special static service in listener.ora for data guard broker to use.

ORA-12514 When Using a Database Link

A database link is just like a client which is trying to connect the remote database.

SQL> conn hr/hr
Connected.
SQL> select first_name from employees@ora11g_hr;
select first_name from employees@ora11g_hr
                                 *
ERROR at line 1:
ORA-12514: TNS:listener does not currently know of service requested in connect descriptor

If the database link has been reliable for a long time, you should check the availability of the remote database. The causes that we have talked about in the section of ORA-12514 in Common Situations are still sustained. They may be:

• The remote database is down. This is the most common cause of ORA-12514.
• The connect descriptor in the local tnsnames.ora has been changed.
• The service name of the remote database has been changed.
• Another listener is used for servicing the remote database.

Usually, this type of ORA-12514 does not complain about the database link, except that you defined the database link with its own connect descriptor.

For example, we can create a database link with a full connect descriptor like this:

SQL> create database link ora11g_hr connect to hr identified by hr using '(DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = oracle-11g-server)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED)(SERVICE_NAME = ORCL)))';

Database link created.

As you can see, we did not use a connect identifier, instead, we use a full connect descriptor. Therefore, if there’s anything wrong with the connect descriptor, we have to drop the database link then create a new one for solving ORA-12514.

In previous articles I have explored various reasons why a client process might not be able to connect to an Oracle database. In Help! I can’t connect to my database … I presented an overview of the process. I followed that with articles going into more depth on the types of problems that can prevent the request from reaching the host server. Now I would like to look at problems that can arise once the request actually arrives at the listener, in particular “ORA-12514: TNS:listener does not currently know of service requested in connect descriptor”.

For this demonstration I will generate the error then go through the standard analysis and solution. After that, I will explore some of the interesting factors that flow from this.

The Error – ORA-12514

Before we get into specifics of debugging ORA-12514, let’s create a test case and mention some general principles.

C:>sqlplus scott/tiger@tulsa

SQL*Plus: Release 11.2.0.1.0 Production on Mon Jan 18 15:28:47 2016

Copyright (c) 1982, 2010, Oracle.  All rights reserved.

ERROR:
ORA-12514: TNS:listener does not currently know of service requested in connect
descriptor


Enter user-name:

Fig. 1

Of course the very first thing anyone should do when confronted with an Oracle error is to check the official description. There are many sources on the web, but I like to start with ‘oerr’ utility on the server ..

[oracle@vmlnx01 admin]$ oerr ora 12514
12514, 00000, "TNS:listener does not currently know of service requested in connect descriptor"
// *Cause:  The listener received a request to establish a connection to a
// database or other service. The connect descriptor received by the listener
// specified a service name for a service (usually a database service)
// that either has not yet dynamically registered with the listener or has
// not been statically configured for the listener.  This may be a temporary
// condition such as after the listener has started, but before the database
// instance has registered with the listener.
// *Action:
//  - Wait a moment and try to connect a second time.
//  - Check which services are currently known by the listener by executing:
//    lsnrctl services
//  - Check that the SERVICE_NAME parameter in the connect descriptor of the
//    net service name used specifies a service known by the listener.
//  - If an easy connect naming connect identifier was used, check that
//    the service name specified is a service known by the listener.
//  - Check for an event in the listener.log file.

Fig. 2

The error is pretty self-explanatory: “listener does not currently know of service requested in connect descriptor”. Of course, this could be because the client incorrectly specified the service name for the database, or because the listener really doesn’t know of a service that it should know.

The description returned by oerr also outlines a course of action to resolve the problem. By following this outline, we should come to know where the actual problem lies. Let’s fill in the details on each one in turn.

Wait and try again.

One of the features of Oracle database is the ability to register itself with the listener. This is referred to as “dynamic registration”. The listener does not have to be specifically configured to know about the database instance. The database will contact the listener every several seconds and register itself. The “wait and try again” solution is predicated on the assumption that we simply haven’t waited long enough for the database to register itself. Since the database instance performs dynamic registration every sixty seconds (if not more often), the “wait and try again” solution should only work if the error occurred immediately after database startup.

Check which services are known by the listener

Many people try to answer this question by looking at the listener configuration file, listener.ora. However, this is insufficient for one big reason: dynamic registration is not dependent on any listing in listener.ora. And as a result of that, for most cases it is not even necessary to have a listener.ora file at all.

The one reliable way to tell what instances and services the listener knows about is to query it directly, using the lsnrctl utility.

 
oracle:tulsa$ lsnrctl status

LSNRCTL for Linux: Version 12.1.0.2.0 - Production on 18-JAN-2016 15:03:12

Copyright (c) 1991, 2014, Oracle.  All rights reserved.

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=vblnxsrv02.localdomain)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version 12.1.0.2.0 - Production
Start Date                18-JAN-2016 14:43:59
Uptime                    0 days 0 hr. 19 min. 12 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /u01/app/oracle/product/12.1.0/dbhome_1/network/admin/listener.ora
Listener Log File         /u01/app/oracle/diag/tnslsnr/vblnxsrv02/listener/alert/log.xml
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=vblnxsrv02.localdomain)(PORT=1521)))
  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1521)))
Services Summary...
Service "tulsa" has 1 instance(s).
  Instance "tulsa", status READY, has 1 handler(s) for this service...
Service "tulsaXDB" has 1 instance(s).
  Instance "tulsa", status READY, has 1 handler(s) for this service...
The command completed successfully

oracle:tulsa$

Fig. 3

We see in figure 3, above, that the listener knows of two services, “tulsa”, and “tulsaXDB”, both associated with the instance “tulsa”. (The service “tulsaXDB” is for special use and is of no real concern for our present discussion.) Notice that the status is listed as “READY”. This is a definitive indication that the registration is dynamic. By contrast, look at the content of listener.ora:

 
# listener.ora Network Configuration File: /u01/app/oracle/product/12.1.0/dbhome_1/network/admin/listener.ora
# Generated by Oracle configuration tools.

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = vblnxsrv02.localdomain)(PORT = 1521))
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
    )
  )

Fig. 4

Notice in Fig. 4 that there is no mention of any service or SID at all, yet we know that the listener has registered service “tulsa” with SID “tulsa”.

At this point in your problem resolution, you must ask yourself if the listener has registered the database you are expecting. If not, you need to resolve that. If the expected database is not reported by the listener, then ORA-12514 is just an indication of a more fundamental problem, which I will discuss in more depth in a future article. In our current case, we want to connect to “tulsa”, and the listener knows about “tulsa”, so we should continue to the next possible problem.

Check the SERVICE_NAME parameter in the connect descriptor

At this point we know that the listener has a registration for “tulsa”. And didn’t we request a connection to “tulsa” in Fig. 1? Well, no, not really. We specified “tulsa” as the net service name, but that is not necessarily what gets passed in the connect descriptor.

The net service name in our connection request (see Fig. 1, line 1) is nothing more than an alias which gets resolved to the final connect descriptor. As described in my previous article Troubleshooting ORA-12154, there are several methods of resolving a net service name to a connect descriptor. In our case, we are relying on resolution via tnsnames.ora, so our request for “tulsa” was located in tnsnames, and information found there was used to construct the final connect descriptor.

Our tnsnames.ora entry for “tulsa” looks like this:

TULSA =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = vblnxsrv02)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = fubar)
    )
  )

Fig. 5

At Fig. 5, line 7, we see that the actual service name specified is “fubar”. Normally, one might expect the SERVICE_NAME specification to be the same as the alias, but this cannot be taken for granted and must be checked. If they do not match, you must ask yourself, “why?” There may be legitimate reasons, or it could be a simple typographical error, or it could be that the person who set it up really didn’t understand what they were doing. In the above case I deliberately made a mismatch for the express purpose of creating an error and making a point.

Of course, we could be looking at the wrong tnsnames.ora. Let’s run this to ground a bit more thoroughly.

First, let’s try a tnsping and see if the reported connect descriptor matches what we saw in our tnsnames.ora

C:>tnsping tulsa

TNS Ping Utility for 64-bit Windows: Version 11.2.0.1.0 - Production on 18-JAN-2
016 15:57:51

Copyright (c) 1997, 2010, Oracle.  All rights reserved.

Used parameter files:
C:apporacleproduct11.2.0client_1networkadminsqlnet.ora


Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)
(HOST = vblnxsrv02)(PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME = fubar)))
OK (30 msec)

C:>

Fig. 6

At line 14, we see the same bogus SERVICE_NAME = fubar, pretty much confirming that we were looking at the correct tnsnames.ora.

As one final nail in the coffin, we can look at the listener log on the database server. The plain text version of this log will be located at $ORACLE_BASE/diag/tnslsnr/<hostname>/listener/trace/listener.log. Looking at my log, I find the following entry:

18-JAN-2016 15:24:20 * (CONNECT_DATA=(SERVICE_NAME=fubar)(CID=(PROGRAM=C:apporacleproduct11.2.0client_1binsqlplus.exe)(HOST=STEVENS-NB-04)(USER=ed))) * (ADDRESS=(PROTOCOL=tcp)(HOST=192.168.56.1)(PORT=64942)) * establish * fubar * 12514
TNS-12514: TNS:listener does not currently know of service requested in connect descriptor

Fig. 7

You may have to scroll the above display to the right, but you can clearly see in line 1 that the listener received a request to connect to “SERVICE_NAME=fubar”. The last item on the line logging the request is the return code, which in this case is “12514”. This line is followed immediately by a line explicitly reporting the 12514. At this level, it is reported as a TNS error instead of an ORA error but that distinction is merely a matter of where, within the call stack, the error is being reported. It is still the same error.

The fix

At this point it should be obvious that the root problem is an incorrect specification of SERVICE_NAME in our tnsnames.ora file. Let’s fix that:

TULSA =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = vblnxsrv02)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = tulsa)
    )
  )

Fig. 8

And prove our fix

C:>sqlplus scott/tiger@tulsa

SQL*Plus: Release 11.2.0.1.0 Production on Mon Jan 18 16:22:34 2016

Copyright (c) 1982, 2010, Oracle.  All rights reserved.


Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, OLAP, Advanced Analytics and Real Application Testing opt
ions

SQL>

Fig. 9

Conclusion

In this article I have demonstrated the connection between what the client requests and what the listener expects. The next logical issue was mentioned in passing when we looked at the services registered with the listener. In my next article I will discuss the methods by which a database becomes registered with the listener.

Film at eleven …