split interval middleware sends query when start equals false (#5714)

Signed-off-by: Ben Ye <[email protected]>

Signed-off-by: Ben Ye <[email protected]>

internal/cortex/querier/queryrange/split_by_interval.go

@@ -70,6 +70,11 @@ func (s splitByInterval) Do(ctx context.Context, r Request) (Response, error) {
 }
 
 func splitQuery(r Request, interval time.Duration) ([]Request, error) {
+	// If Start == end we should just run the original request.
+	if r.GetStart() == r.GetEnd() {
+		return []Request{r}, nil
+	}
+
 	// Replace @ modifier function to their respective constant values in the query.
 	// This way subqueries will be evaluated at the same time as the parent query.
 	query, err := evaluateAtModifierFunction(r.GetQuery(), r.GetStart(), r.GetEnd())

internal/cortex/querier/queryrange/split_by_interval_test.go

@@ -85,6 +85,23 @@ func TestSplitQuery(t *testing.T) {
 			},
 			interval: day,
 		},
+		{
+			input: &PrometheusRequest{
+				Start: 60 * 60 * seconds,
+				End:   60 * 60 * seconds,
+				Step:  15 * seconds,
+				Query: "foo",
+			},
+			expected: []Request{
+				&PrometheusRequest{
+					Start: 60 * 60 * seconds,
+					End:   60 * 60 * seconds,
+					Step:  15 * seconds,
+					Query: "foo",
+				},
+			},
+			interval: day,
+		},
 		{
 			input: &PrometheusRequest{
 				Start: 0,