On Fri, Sep 29, 2017 at 2:03 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
Jeff Janes <jeff.janes@gmail.com> writes: > On Fri, Sep 29, 2017 at 6:43 AM, <zam6ak@gmail.com> wrote: >> We use clock_timestamp() function in our code and I have noticed that in PG >> 10 RC1 it returns same values across rows...
> Probably not an issue of the different versions, but rather different > compilers (or maybe different hardware?).
AFAICS, our code in this area (see src/port/gettimeofday.c) has not changed since 9.5. I'm suspicious of a platform change. > I get the same behavior on these two versions: > ... > and that behavior is that the timestamp jumps 500 usec at a time, despite > looking as if it might have usec granularity:
What gettimeofday.c does is to use GetSystemTimePreciseAsFileTime() if it can get hold of that, otherwise fall back to GetSystemTimeAsFileTime(). I don't see anything very specific in Windows' documentation about the resolution to be expected from either one, but I wonder if the OP's 9.6 installation is using the former while for some reason his 10rc1 installation is using the latter.
Just for the record, both PG instances I tested this on are running on the same OS system in same VM, just different ports.
I also tried Windows Server 2012 (in VM) and am getting same issue.