phpstudy自带的mysql，服务器重启后，就不能以innodb模式启动。不知道为什么，my.ini里 错误日志error_log，临时文件路径 tempdir都没有设置。设置好error_log后，报错
181024 8:49:19 InnoDB: Mutexes and rw_locks use Windows interlocked functions
181024 8:49:19 InnoDB: Compressed tables use zlib 1.2.3
181024 8:49:19 InnoDB: Error: unable to create temporary file; errno: 2
181024 8:49:19 [ERROR] Plugin 'InnoDB' init function returned error.
181024 8:49:19 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
181024 8:49:19 [ERROR] Unknown/unsupported storage engine: INNODB
181024 8:49:19 [ERROR] Aborting
关键的问题是 InnoDB: Error: unable to create temporary file; errno: 2，不能创造临时文件。设置了tempdir="c:\temp\"也不行，折腾了好久，原来是要用双斜杠，tempdir="c:\\temp\\"