Silly precision in a timing macros
Andreas Ericsson
ae at op5.se
Fri Oct 29 02:45:17 CEST 2004
Jason Martin wrote:
> On Fri, Oct 29, 2004 at 09:51:40AM +1000, Stanley Hopcroft wrote:
>
>>Do you really need this accuracy ?
>>Milliseconds are fine for me. Prob Seconds are also.
>
> Seconds would be too course for measuring database row insertion
> times, perhaps tenths-of-a-milisecond would be enough. I was
> raising the point only because I happened to have seen that data
> in my output, not because I particularly needed it.
>
Database inserts are rarely done in less than 1 millisecond. The steps
involved are;
parse command
evaluate values
hash values
insert in hash tables
copy to in-house memory
flush to disk
If you want exact timings, do 1000 or 10000 consecutive inserts and get
an average. It will be much more accurate than timing a single insert
anyway, and production applications shouldn't really bother with timing
each insert. That's what testcases are for.
--
Andreas Ericsson andreas.ericsson at op5.se
OP5 AB www.op5.se
Lead Developer
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