ORA-31688: Worker process string failed during startup.
Cause: The worker process whose name is listed failed during startup.
Action: Refer to any following error messages for possible actions. Check the trace log for the failed process to see if there is any information about the failure. Correct the error, if possible, and try the operation again. If the error occurs again, contact Oracle Customer Support and report the error.
ORA-31688错误是指Worker process failed during startup过程中失败，这是一个非常常见的错误，通常会出现在Oracle底层日志中，一般表现为以下提示错误：
ORA-31688：worker process “string” failed during startup
这里string指的是处理该错误的Oracle进程的名称。这通常是一个相对而言很简单的错误，造成这个错误的原因一般是系统的内存不足或磁盘的I/O性能不的够的导致的，也有可能是客户端与服务器之间网络连接出现中断。
1、检测并检查磁盘I/O的性能，确定磁盘的I/O性能是否足够支撑Oracle使用;
2、检查客户端与服务器之间的网络状况，确定网络是否稳定;
3、如果系统出现内存不足，检查系统是否有多余的进程或连接占用系统内存，结束占用内存过多的连接或进程；
4、如果系统有多个依赖他们必须运行的特殊进程，那么请确保它们都启动了，并且正常运行.