How to Fix 'org.postgresql.util.PSQLException: FATAL: sorry, too many clients already'?

Resolving "org.postgresql.util.PSQLException: FATAL: sorry, too many clients already"

Error Explanation

This error occurs when your code attempts to establish more connections to the PostgreSQL database than the allowed limit. The error message signifies that the maximum number of concurrent connections has been reached.

Debugging Strategies

Close Connections Promptly:
Ensure that you close connections properly using conn.close(). Leaving connections open indefinitely, even when classes are garbage collected, prevents the database from releasing them.

Identify Open Connections:
Execute the following SQL query to view open connections:

SELECT * FROM pg_stat_activity;

Check Current Connection Count:
Use the following query to determine the number of active connections:

SELECT COUNT(*) FROM pg_stat_activity;

Maximize Concurrent Connections:
Locate the max_connections setting in the postgresql.conf file and increase its value to accommodate your application's needs.

Additional Tips

Track Connections:
Assign different usernames and passwords to programs accessing the database to isolate potential culprits.

Analyze Stack Traces:
Examine exception stack traces to pinpoint where connections are being created and closed improperly.

Setting Maximum Connections

To increase the maximum number of concurrent connections, edit the postgresql.conf file:

1. Find the max_connections setting.
2. Adjust the value to the desired maximum (within hardware constraints).
3. Restart the PostgreSQL database service.

Usage Limitations

While increasing the maximum connections can mitigate the error, it's important to note that excessive connections can:

• Exhaust system resources.
• Degrade database performance.

Consider using connection pooling software for efficient management of high-volume connections.

The above is the detailed content of How to Fix 'org.postgresql.util.PSQLException: FATAL: sorry, too many clients already'?. For more information, please follow other related articles on the PHP Chinese website!