Re: Overhead for stats_command_string et al, take 2

Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes:
> Average of 5 runs, for the first two cases, on the x86 machine that
> shows high overhead in gettimeofday.

> I used only 30000 SELECT 1 queries instead of 100k.

> 30000 SELECT 1;
> HEAD 8.1
> no overhead 21.9 23.1
> stats_command_string=1 22.4 36.6

> BEGIN; 30000 SELECT 1; COMMIT;
> HEAD 8.1
> no overhead 19.1 20.3
> stats_command_string=1 19.4 30.3

> It can be observed that HEAD in the no overhead case is actually faster
> than 8.1 on this machine.

That's more or less what I would have hoped to find, because we're
always finding ways to squeeze out bits of overhead here and there.
I wonder why your results are different from what I got on my older
machine? I'll have to break out oprofile again and try to see what's
happening there.

regards, tom lane