ORA-12500, TNS:listener failed to start a dedicated server process
This solution covers the following topics:
A. TNS-12500 on Microsoft Windows NT
B. Intermittent TNS-12500 Errors on Microsoft Windows NT
A. TNS-12500 on Microsoft Windows NT
-----------------------------------------
1. Please make sure that the userid that installed/started
oracle, and started the listener is administrator.
2. Go to the Control Panel by clicking on [START]-->
[Settings]---> [Control Panel] and then double click
on "Services". A window is displayed which
looks similar to this:
+---------------------------------------------------------+
| |
| Service Status Startup |
+---------------------------------------------------------+
|OracleNamesService80 Manual |
|OracleServiceORCL Started Auto |
|OracleStartORCL Started Auto |
|OracleTNSListener Started Auto |
|OracleTNSListener80 Manual |
|OracleWebAssistant Manual |
|pcANYWHERE Service Started Manual |
+---------------------------------------------------------+
Look at "OracleService" and "OracleStart". These two
services are followed by your SID name (in this case ORCL).
These services should be started. If they are not click
on the [START] button on the right side of the dialog box.
3. Verify the SID names shown with "OracleService" and
"OracleStart" in the Control Panel:Services are the same
SID names in the client's TNSNAMES.ORA and the server's
LISTENER.ORA files.
4. Make sure that the listener is logged on as the System
Account. You can check this by going into Control
Panel/Services highlight the OracleTNSListener then
click on Startup. The listener should be logged on as
the System Account. Once you make this change make
sure that you stop and start the listener.
5. Make sure that the tnsnames.ora file doesn't specify the
ORACLE_HOME parameter in the connect_data section. If it
does, remove it.
6. You may want to simply try restarting your instance.
B. Intermittent TNS-12500 Errors on Microsoft Windows NT
---------------------------------------------------------
1. Increase the amount of memory available to the system
either by removing unnecessary processes or increasing
the amount of physical memory.
2. Increasing the amount of swap space will also
temporarily help relieve the symptoms.
3. Disable OTRACE. OTRACE is a tracing feature that can
cause many problems. OTRACE is enabled by default.
To disable OTRACE:
a. Stop the Oracle database.
b. Go to the orant/otrace/admin directory.
c. Delete all files with a ‘.dat’ extension.
d. Restart the Oracle database.
4. The TNS-12500 can be a result of the 'processes'
parameter in the init<sid>.ora file being too low.