Re: Restart pg_usleep when interrupted

> What does your testing show when you don't have
> the extra check, i.e.,
>
> struct timespec delay;
> struct timespec remain;
>
> delay.tv_sec = microsec / 1000000L;
> delay.tv_nsec = (microsec % 1000000L) * 1000;
>
> while (nanosleep(&delay, &remain) == -1 && errno == EINTR)
> delay = remain;
>

This is similar to the first attempt [1],

+pg_usleep_handle_interrupt(long microsec, bool force)
{
if (microsec > 0)
{
#ifndef WIN32
struct timespec delay;
+ struct timespec remaining;

delay.tv_sec = microsec / 1000000L;
delay.tv_nsec = (microsec % 1000000L) * 1000;
- (void) nanosleep(&delay, NULL);
+
+ if (force)
+ while (nanosleep(&delay, &remaining) == -1 && errno == EINTR)
+ delay = remaining;

but Bertrand found long drifts [2[ which I could not reproduce.
To safeguard the long drifts, continue to use the &remain time with an
additional safeguard to make sure the actual sleep does not exceed the
requested sleep time.

[1] https://www.postgresql.org/message-id/7D50DC5B-80C6-47B5-8DA8-A6C68A115EE5%40gmail.com
[2] https://www.postgresql.org/message-id/ZoPC5IeP4k7sZpki%40ip-10-97-1-34.eu-west-3.compute.internal

Regards,

Sami