Re: Remove condition variables from injection wait logic.

On Wed, Aug 20, 2025 at 11:20:11AM +0500, Kirill Reshke wrote:
> $sub proposed in a nearby thread. Looks like we have a consensus that
> $subj is beneficial.
> I implemented  necessary legwork, namely a clock-based check in the
> wait() routine, PFA. I'm not sure the default pg_sleep argument of 50
> millisecond is good, but it is fast enough to not spot any difference
> in by-hand testing.

I may be missing something, but I don't think that we have reached a
consensus yet.  There is the argument of AIO and being able to
broadcast writes.

+        pgstat_report_wait_start(injection_wait_event);
+#define DEFAULT_INJ_POINT_SLEEP_MICROSEC 50000L /* 50 milliseconds */
+        pg_usleep(DEFAULT_INJ_POINT_SLEEP_MICROSEC);

I would not object to that if that's the actual consensus as we don't
have a strong requirement for condition variables when it comes to
testing.  That's just a more efficient implementation, and it makes
the tests faster.  If we do that, I'd suggest to choose a cap and a
variable wait time, that increases across iterations to still make the
wait more responsive on faster machines.

Your patch lacks a pgstat_report_wait_end().
--
Michael