Fix WaitLatch(NULL) on Windows.

macdice · macdice · commit a7e65dc88b6f · 2020-11-25T17:55:49.000+13:00
Further to commit 733fa9a, on Windows when a latch is triggered but we aren't currently waiting for it, we need to locate the latch's HANDLE rather than calling ResetEvent(NULL). Author: Kyotaro Horiguchi <horikyota.ntt@gmail.com> Reported-by: Ranier Vilela <ranier.vf@gmail.com> Discussion: https://postgr.es/m/CAEudQArTPi1YBc%2Bn1fo0Asy3QBFhVjp_QgyKG-8yksVn%2ByRTiw%40mail.gmail.com
diff --git a/src/backend/storage/ipc/latch.c b/src/backend/storage/ipc/latch.c
@@ -1835,7 +1835,11 @@ WaitEventSetWaitBlock(WaitEventSet *set, int cur_timeout,
 
 	if (cur_event->events == WL_LATCH_SET)
 	{
-		if (!ResetEvent(set->latch->event))
+		/*
+		 * We cannot use set->latch->event to reset the fired event if we
+		 * aren't waiting on this latch now.
+		 */
+		if (!ResetEvent(set->handles[cur_event->pos + 1]))
 			elog(ERROR, "ResetEvent failed: error code %lu", GetLastError());
 
 		if (set->latch && set->latch->is_set)
