ORA-12500: TNS:listener failed to start a dedicated server process
Cause: The process of starting up a dedicated server process failed. The executable could not be found or the environment may be set up incorrectly.
Action: Turn on tracing at the ADMIN level and reexecute the operation. Verify that the ORACLE Server executable is present and has execute permissions enabled. Ensure that the ORACLE environment is specified correctly in LISTENER.ORA. The Oracle Protocol Adapter that is being called may not be installed on the local hard drive. Please check that the correct Protocol Adapter are successfully linked. If error persists, contact Oracle Customer Support.
ORA-12500 是Oracle数据库中常见的错误，是由TNS Listener没有能够启动专用服务器进程引起的。
该ORA-12500错误表明TNS Listener在尝试启动被请求数据库上的专用服务器进程时失败了。可能是因为TNS Listener在启动进程时发生错误，或者是因为没有足够的资源进程来启动。
这种错误通常发生在数据库启动时，但也可能在数据库运行时发生，因为服务器进程可能会失败或被中断。
1.检查操作系统确认是否有足够的内存来启动服务器进程
2.检查TNS Listener日志文件，查看是否有额外的错误信息，用于定位错误
3.重新启动TNS Listener
4.如果第一步和第二步都没有获得有关错误的信息，则建议启动一个新的数据库会话，以确保能够以安全的方式访问数据库
5.如果重新启动TNS Listener仍然不起作用，则应检查服务器的安装程序，看看是否存在一个已知的问题