ORA-12520: TNS:listener could not find available handler for requested type of server

文档解释

ORA-12520: TNS:listener could not find available handler for requested type of server

Cause: None of the known and available service handlers for requested type of server (dedicated or shared) are appropriate for the client connection.

Action: Run “lsnrctl services” to ensure that the instance(s) have registered with the listener and that the appropriate handlers are accepting connections.

。

ORA-12520: TNS Listener could not find available handler for requested type of server是一个基于Oracle数据库的例外错误码，指明数据库监听器没有发现用户所请求服务器类型的可用处理程序。

官方解释

常见案例

正常处理方法及步骤

①确认监听器是否已经运行，在Windows操作系统上可以运行“lsnrctl status”命令查看；

②检查TNSNAMES.ORA文件的配置以确保正确的TNS监听器和服务名正确，也就是说可以确保在计算机上安装了正确的Oracle客户端，客户端与服务器是兼容的。

③使用tnsping来检查连接，以确保TNS监听器或客户端/服务器之间的通讯正常。

④重新触发监听器，运行“lsnrctl start”命令启动监听器。