Oracle error
ORA-12519
ORA-12519: TNS:no appropriate service handler found
What usually causes it
The listener blocked new connections, usually because the instance is at or near its PROCESSES limit.
What to check first
Check processes and sessions against their limits.
Scripts that help
- Processes and sessions against their limitsCurrent and peak usage of processes, sessions and transactions since startup. A PEAK % near 100 means the next connection storm will hit ORA-00020.
- Session count by user and machineWho is connected, from where, and how many are active. The quickest way to spot a connection pool that has run away.