Thread

Re: [HACKERS] Execution time

Mattias Kregert <matti@algonet.se> — 1998-03-09T12:22:43Z

Shiby Thomas wrote:
> 
> The time command will give the elapsed, user CPU and System CPU times.
> How do I interpret it as CPU/IO time ?
> 
> Even the -s option of postgres gives those times. Will it be the same as
> using "time postgres" ? Is the System time a reasonable approximation of the
> I/O time and user time that of CPU time ?


I would say they are reasonable approximations, at least for
user==CPU.
Perhaps you need to look at elapsed time too, and from that make some
assumptions about I/O waiting time. I think system time will be lower
if you use SCSI and higher with IDE.
I would count (elapsed time - CPU time) as I/O time.

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