> -----Original Message-----
> From: Tom Lane [mailto:tgl@sss.pgh.pa.us]
> Sent: Monday, March 07, 2005 10:39 AM
> To: John A Meinel
> Cc: Magnus Hagander; Ken Egervari; pgsql-performance@postgresql.org;
> pgsql-hackers-win32@postgresql.org
> Subject: Re: [pgsql-hackers-win32] [PERFORM] Help with tuning
> this query
> (with explain analyze finally)
>
> [...]
> The EXPLAIN ANALYZE instrumentation code will really be happier with a
> straight time-since-bootup counter; by using gettimeofday, it is
> vulnerable to giving wrong answers if someone changes the date setting
> while the EXPLAIN is running. But there is (AFAIK) no such call among
> the portable Unix syscalls. It seems reasonable to me to #ifdef that
> code to make use of QueryPerformanceCounter on Windows. This does not
> mean we want to alter the behavior of gettimeofday() where it's being
> used to find out the time of day.
There is always clock(). It's mandated by ANSI C, but my docs say
that POSIX requires CLOCKS_PER_SEC == 1000000 regardless of actual
timer resolution, which seems a little brain-dead to me.
__
David B. Held
Software Engineer/Array Services Group
200 14th Ave. East, Sartell, MN 56377
320.534.3637 320.253.7800 800.752.8129