sqlite shell 报告 CPU 时间 : what are the units?

Question

当使用带有 .timer on 的 Sqlite shell 时我得到控制台打印，如“CPU 时间:用户 0.062400 sys 0.015600”。如何将其转换为毫秒？是否有其他方法可以在 Sqlite shell 中测量总查询时间(以毫秒为单位)？

Answer 1

单位是秒。见引用:https://github.com/freebsd/pkg/blob/master/external/sqlite/shell.c

该页面的代码快照:

/* Return the difference of two time_structs in seconds */
static double timeDiff(struct timeval *pStart, struct timeval *pEnd){
  return (pEnd->tv_usec - pStart->tv_usec)*0.000001 + 
         (double)(pEnd->tv_sec - pStart->tv_sec);
}

/*
** Print the timing results.
*/
static void endTimer(void){
  if( enableTimer ){
    struct rusage sEnd;
    getrusage(RUSAGE_SELF, &sEnd);
    printf("CPU Time: user %f sys %f\n",
       timeDiff(&sBegin.ru_utime, &sEnd.ru_utime),
       timeDiff(&sBegin.ru_stime, &sEnd.ru_stime));
  }
}

如果您想转换为毫秒，请乘以 1000。