Hello Fabien,
On Sun, 13 Jun 2021 08:56:59 +0200 (CEST)
Fabien COELHO <[email protected]> wrote:
> > I attached a patch for this fix.
>
> The patch mostly works for me, and I agree that the bench should not be in
> a loop on any parameters, even when "crazy" parameters are given…
>
> However I'm not sure this is the right way to handle this issue.
>
> The catch-up loop can be dropped and the automaton can loop over itself to
> reschedule. Doing that as the attached fixes this issue and also makes
> progress reporting work proprely in more cases, and reduces the number of
> lines of code. I did not add a test case because time sensitive tests have
> been removed (which is too bad, IMHO).
I agree with your way to fix. However, the progress reporting didn't work
because we cannot return from advanceConnectionState to threadRun and just
break the loop.
+ /* otherwise loop over
PREPARE_THROTTLE */
break;
I attached the fixed patch that uses return instead of break, and I confirmed
that this made the progress reporting work property.
Regards,
Yugo Nagata
--
Yugo NAGATA <[email protected]>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index dc84b7b9b7..8f5d000938 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -3223,32 +3223,31 @@ advanceConnectionState(TState *thread, CState *st, StatsData *agg)
/*
* If --latency-limit is used, and this slot is already late
* so that the transaction will miss the latency limit even if
- * it completed immediately, skip this time slot and schedule
- * to continue running on the next slot that isn't late yet.
- * But don't iterate beyond the -t limit, if one is given.
+ * it completed immediately, skip this time slot and loop to
+ * reschedule.
*/
if (latency_limit)
{
pg_time_now_lazy(&now);
- while (thread->throttle_trigger < now - latency_limit &&
- (nxacts <= 0 || st->cnt < nxacts))
+ if (thread->throttle_trigger < now - latency_limit)
{
processXactStats(thread, st, &now, true, agg);
- /* next rendez-vous */
- thread->throttle_trigger +=
- getPoissonRand(&thread->ts_throttle_rs, throttle_delay);
- st->txn_scheduled = thread->throttle_trigger;
- }
- /*
- * stop client if -t was exceeded in the previous skip
- * loop
- */
- if (nxacts > 0 && st->cnt >= nxacts)
- {
- st->state = CSTATE_FINISHED;
- break;
+ /* stop client if -T/-t was exceeded. */
+ if (timer_exceeded || (nxacts > 0 && st->cnt >= nxacts))
+ /*
+ * For very unrealistic rates under -T, some skipped
+ * transactions are not counted because the catchup
+ * loop is not fast enough just to do the scheduling
+ * and counting at the expected speed.
+ *
+ * We do not bother with such a degenerate case.
+ */
+ st->state = CSTATE_FINISHED;
+
+ /*otherwise loop over PREPARE_THROTTLE */
+ return;
}
}
