Adjust input value to WaitEventSetWait() in ExecAppendAsyncEventWait().

Etsuro Fujita · Etsuro Fujita · commit a8af856d3257 · 2021-04-06T19:15:00.000+09:00
Adjust the number of events given to WaitEventSetWait() so that it doesn't exceed the maximum number of events in the WaitEventSet given to that function (set->nevents_space) in hopes of making the buildfarm green. Per valgrind failure report from Tom Lane and the buildfarm. Author: Etsuro Fujita Discussion: https://postgr.es/m/3411577.1617289776%40sss.pgh.pa.us
diff --git a/src/backend/executor/nodeAppend.c b/src/backend/executor/nodeAppend.c
@@ -1001,6 +1001,7 @@ ExecAppendAsyncEventWait(AppendState *node)
 	long		timeout = node->as_syncdone ? -1 : 0;
 	WaitEvent   occurred_event[EVENT_BUFFER_SIZE];
 	int			noccurred;
+	int			nevents;
 	int			i;
 
 	/* We should never be called when there are no valid async subplans. */
@@ -1022,8 +1023,9 @@ ExecAppendAsyncEventWait(AppendState *node)
 	}
 
 	/* Wait for at least one event to occur. */
+	nevents = Min(node->as_nasyncplans + 1, EVENT_BUFFER_SIZE);
 	noccurred = WaitEventSetWait(node->as_eventset, timeout, occurred_event,
-								 EVENT_BUFFER_SIZE, WAIT_EVENT_APPEND_READY);
+								 nevents, WAIT_EVENT_APPEND_READY);
 	FreeWaitEventSet(node->as_eventset);
 	node->as_eventset = NULL;
 	if (noccurred == 0)
