ORA-12520 TNS:listener could not find available handler for requested type of server
This is an Oracle Database Server Message. This can be generated by the Oracle Database when running any Oracle program.
What is the cause of ORA-12520 from Oracle 11g ?
None of the known and available service handlers for requested type of server (dedicated or shared) are appropriate for the client connection.
How to deal with ORA-12520 from Oracle 11g ?
Run "lsnrctl services" to ensure that the instance(s) have registered with the listener and that the appropriate handlers are accepting connections.
Contacting Oracle support services ?
Some messages recommend contacting Oracle Support Services to report a problem. Please go here for more information : Oracle Support.
Linked Error Messages
- ORA-12513 TNS:service handler found but it has registered for a different protocol
- ORA-12514 TNS:listener does not currently know of service requested in connect descriptor
- ORA-12515 TNS:listener could not find a handler for this presentation
- ORA-12516 TNS:listener could not find available handler with matching protocol stack
- ORA-12518 TNS:listener could not hand off client connection
- ORA-12519 TNS:no appropriate service handler found
- ORA-12521 TNS:listener does not currently know of instance requested in connect descriptor
- ORA-12522 TNS:listener could not find available instance with given INSTANCE_ROLE
- ORA-12523 TNS:listener could not find instance appropriate for the client connection
- ORA-12524 TNS:listener could not resolve HANDLER_NAME given in connect descriptor
- ORA-12525 TNS:listener has not received client's request in time allowed
- ORA-12526 TNS:listener: all appropriate instances are in restricted mode
- ORA-12527 TNS:listener: all instances are in restricted mode or blocking new connections
- ORA-12528 TNS:listener: all appropriate instances are blocking new connections