Cortex should still send the request to upstream when Start == end

Author: alanprot

pkg/querier/tripperware/queryrange/split_by_interval.go

@@ -76,7 +76,7 @@ func splitQuery(r tripperware.Request, interval time.Duration) ([]tripperware.Re
 		return nil, err
 	}
 	var reqs []tripperware.Request
-	for start := r.GetStart(); start < r.GetEnd(); start = nextIntervalBoundary(start, r.GetStep(), interval) + r.GetStep() {
+	for start := r.GetStart(); start <= r.GetEnd(); start = nextIntervalBoundary(start, r.GetStep(), interval) + r.GetStep() {
 		end := nextIntervalBoundary(start, r.GetStep(), interval)
 		if end+r.GetStep() >= r.GetEnd() {
 			end = r.GetEnd()

pkg/querier/tripperware/queryrange/split_by_interval_test.go

@@ -84,6 +84,23 @@ func TestSplitQuery(t *testing.T) {
 			},
 			interval: day,
 		},
+		{
+			input: &PrometheusRequest{
+				Start: 60 * 60 * seconds,
+				End:   60 * 60 * seconds,
+				Step:  15 * seconds,
+				Query: "foo",
+			},
+			expected: []tripperware.Request{
+				&PrometheusRequest{
+					Start: 60 * 60 * seconds,
+					End:   60 * 60 * seconds,
+					Step:  15 * seconds,
+					Query: "foo",
+				},
+			},
+			interval: day,
+		},
 		{
 			input: &PrometheusRequest{
 				Start: 0,