mysql的"Incorrect key file for table '/tmp/#sql_1194_12.MYI'; try to repair it"问题
线上数据库出现以下错误： Incorrect key file for table '/tmp/#sql_1194_1.MYI'; try to repair it Got an error from unknown thread, XXXX/storage/myisam/mi_write.c:223
通过查看源码，在mi_write函数的223行报错。mi_write.c:44/* Write new record to database */int mi_write (MI_INFO * info, uchar *record)
而这里是一段err处理逻辑，跳转到err的函数是mi_write.c:142行的write_record函数。而该函数的实现是_mi_write_static_record 函数。mi_statrec.c:21int _mi_write_static_record (MI_INFO * info, const uchar * record)
到这里实际还没有结束，还没有完全显示出具体操作的逻辑。继续调试代码，该函数调用了mi_nommap_pwrite函数。mi_dynrec.c:255 /* wrapper for mysql_file_pwrite in case if mmap isn't used */size_t mi_nommap_pwrite (MI_INFO * info, const uchar * Buffer, size_t Count , my_off_t offset, myf MyFlags)
而这个函数调用mysql_file_pwrite函数。这里就比较清楚了，实际操作就是写文件了。确定的是写文件失败了。而之所以写文件的位置是/tmp，通过查看发现，该表有复杂的sql查询，用到了临时表。并且临时表的大小甚至达到了1G，导致了/tmp下的空间不足，从而导致错误。
