ORA-12518: TNS: listener could not hand off client connection tips

ORA-12518: TNS:listener could not hand off client connection

Cause: The process of handing off a client connection to another process failed.

Action: Turn on listener tracing and re-execute the operation. Verify that the listener and database instance are properly configured for direct handoff. If problem persists, call Oracle Support



Question:
With Oracle 10g using a Windows platform, how do I resolve ORA-12518?
Answer:
ORA-12518 is often due to network issues, and in HP-UX, there are various bugs causing ORA-12518.
In reference to your platform, there are a few resolutions that may be available for ORA-12518:

• Try looking in the EventLog to check out network connections and associated errors, as well as the alert log in the database.  ORA-12518 can also be thrown along with a database crash.
• Look in the windows service for your Oracle service status
  • start--->run--->services.msc
• The server may be in need of a swap memory to disk as it runs out of memory space.  Sometimes, Oracle processes can take up alot of memory.  If you think this is causing ORA-12518 in your case, you can try this workaround:
  • set parameter to DIRECT_HANDOFF_TTC_LISTENER=OFF in listener.ora
  • restart listener
• You may also want to consider making he large_pool_size larger.