ORA-12519, TNS: no appropriate service handler found

ORA-12519, TNS: no appropriate service handler found

Sometimes it can be connected to the Oracle database, and sometimes it cannot be connected.

It may be that the current number of connections on the Oracle database has exceeded the maximum number it can process.

First, you must use the DBA role to log on.

Select count (*) from v $ process -- current number of connections

Select value from v $ parameter where name = 'processs' -- maximum number of connections allowed by the database

Modify the maximum number of connections:

Alter system set processses = 300 scope = spfile;

Restart the database:

Shutdown immediate;

Startup;

-- View which users are currently using data

SELECT oSUSEr, a. username, cpu_time/executions/1000000 |'s ', SQL _fulltext, machine

From v $ session a, v $ sqlarea B

Where a. SQL _address = B. address order by cpu_time/executions desc;