Square DBA – Oracle DBA Talk

ORA-12518 TNS listener could not hand off client connection

Have you ever seen the error “ORA-12518 TNS listener could not hand off client connection”? I did yesterday and it was a pretty simple fix.

It turns out the processes for a particular instance was set too low. You can see how many processes are running via this command:

select count(*) from v$process;

If you want to see what your threshold is set to run:

show parameter processes;

To change the number of processe run this command:

ALTER SYSTEM SET processes=250 SCOPE=spfile;

Unfortunately this requires you to restart the database for the new value takes affect. To see the new value in the spfile you can run this command:

SELECT value FROM v$spparameter WHERE name='processes';