ora-12516, tns:listener could

ORA-12516是Oracle数据库的一个错误代码，表示TNS监听程序无法处理当前的连接请求。这通常是由于监听程序已经达到了其最大连接数限制，无法再处理新的连接请求所致。要解决这个问题，可以通过增加监听程序的最大连接数限制或者优化数据库连接池的使用来缓解这个问题。

相关问题

ORA-12516, TNS:listener could not find available handler with matching protocol stack

This error message typically indicates that the Oracle listener process is unable to establish a connection to a database instance. There may be several causes for this issue, including:

1. Insufficient resources: The listener process may not have enough available resources to handle incoming connections. This could be due to limited system resources or heavy load on the server.

2. Database instance not available: The database instance that the listener is trying to connect to may not be available or may have been shut down.

3. Incorrect configuration: The listener configuration may be incorrect, preventing it from properly connecting to the database instance.

To resolve this issue, you can try the following steps:

1. Increase resources: If the issue is due to insufficient resources, you can try increasing the available resources on the server.

2. Check database availability: Verify that the database instance is available and running.

3. Check listener configuration: Verify that the listener configuration is correct and that it is able to connect to the database instance.

4. Restart listener: If all else fails, try restarting the listener process and see if that resolves the issue.

org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Listener refused the connection with the following error: ORA-12516, TNS:listener could not find available handler with matching protocol stack)

这个错误表示数据库连接池无法创建可池化的连接工厂，原因是连接监听程序拒绝了连接，报错信息是ORA-12516，即监听程序无法找到与匹配协议栈的可用处理程序。这通常是由于数据库连接池中的连接数超过了数据库实例的最大连接数限制所致。您可以尝试增加数据库实例的最大连接数限制，或者优化您的程序以减少对数据库的连接请求。