In the development process, the Oracle database is sometimes connected, sometimes not even, prompting the following exception "Ora-12519:tns:no appropriate service handler found resolved", It is possible that the current number of connections on the database has exceeded the maximum value it can handle.
– View the current number of connections:
Select Count (* from v$process;
– Maximum number of connections allowed for the database:
Select from where = ' Processes ';
– Modify the maximum number of connections:
Alter Set = - = SPFile;
– Restart the database:
shutdown Immediate;startup;
– see which users are currently using the data
SELECT osuser, a.username,cpu_time/executions/1000000| | from where=order by Cpu_time/desc ;
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Queries and settings for the number of current connections and maximum connections for Oracle databases