ORA-12516 TNS: Listeners cannot find available handlers that meet protocol stack requirements

ORA-12516 TNS: Listeners cannot find available handlers that meet protocol stack requirements

Problem scenario:

A previous database was used for testing (department A). Last night, another test department (Department B) came to test the program. Two users were created on the database and imported data, this afternoon, I suddenly received a phone call from the staff of the two Departments and said that the database could be connected after a while. It was strange at the time, because I used other users to connect to the Database 10 minutes ago. Result when the client test is passed, the ORA-12516 TNS is reported: The Listener cannot find the available handler that meets the protocol stack requirements.

When I saw this error, I did not reflect what went wrong. Then the Department A owner asked me to export the department B data and asked them to find another machine for testing. When I export data of these two users on the server, an error is reported directly. When I log on to the database with one of the two users, the error message is obvious: the maximum process data in the database is 150. So far, I know why?

Solution:

1. Log On Through the sysdba user

2. view the current process count

Select count (*) from v $ processes

We can see 149 processes.

The value of show parameter processes is 150 (the database was created by another user)

3. Change the number of processes

Alter system set processees = 500 scope = spfile

4. Shut down the database

Shutdown immediate

5. Start the database to make the configuration take effect.

Startup;