Merge pull request #8234 from influxdata/js-8230-fix-window-computation-overflow

Prevent overflowing or underflowing during window computation

CHANGELOG.md

@@ -33,6 +33,7 @@
 - [#8175](https://github.com/influxdata/influxdb/issues/8175): Ensure the input for certain functions in the query engine are ordered.
 - [#8171](https://github.com/influxdata/influxdb/issues/8171): Significantly improve shutdown speed for high cardinality databases.
 - [#8177](https://github.com/influxdata/influxdb/issues/8177): Fix racy integration test.
+- [#8230](https://github.com/influxdata/influxdb/issues/8230): Prevent overflowing or underflowing during window computation.
 
 ## v1.2.2 [2017-03-14]
 

influxql/iterator.go

@@ -858,23 +858,34 @@ func (opt IteratorOptions) Window(t int64) (start, end int64) {
 		// with the duration.
 		dt += int64(opt.Interval.Duration)
 	}
-	t -= dt
+
+	// Find the start time.
+	if MinTime+dt >= t {
+		start = MinTime
+	} else {
+		start = t - dt
+	}
 
 	// Look for the start offset again because the first time may have been
 	// after the offset switch. Now that we are at midnight in UTC, we can
 	// lookup the zone offset again to get the real starting offset.
 	if opt.Location != nil {
-		_, adjustedOffset := opt.Zone(t)
+		_, adjustedOffset := opt.Zone(start)
 		// Do not adjust the offset if the offset change is greater than or
 		// equal to the duration.
 		if o := startOffset - adjustedOffset; o != 0 && abs(o) < int64(opt.Interval.Duration) {
 			startOffset = adjustedOffset
 		}
 	}
+	start += int64(opt.Interval.Offset) - startOffset
 
-	// Apply the offset.
-	start = t + int64(opt.Interval.Offset) - startOffset
-	end = start + int64(opt.Interval.Duration)
+	// Find the end time.
+	if dt := int64(opt.Interval.Duration) - dt; MaxTime-dt <= t {
+		end = MaxTime
+	} else {
+		end = t + dt
+	}
+	end += int64(opt.Interval.Offset) - startOffset
 
 	// Retrieve the zone offset for the end time.
 	if opt.Location != nil {

influxql/iterator_test.go

@@ -1067,6 +1067,44 @@ func TestIteratorOptions_Window_Location(t *testing.T) {
 	}
 }
 
+func TestIteratorOptions_Window_MinTime(t *testing.T) {
+	opt := influxql.IteratorOptions{
+		StartTime: influxql.MinTime,
+		EndTime:   influxql.MaxTime,
+		Interval: influxql.Interval{
+			Duration: time.Hour,
+		},
+	}
+	expected := time.Unix(0, influxql.MinTime).Add(time.Hour).Truncate(time.Hour)
+
+	start, end := opt.Window(influxql.MinTime)
+	if start != influxql.MinTime {
+		t.Errorf("expected start to be %d, got %d", influxql.MinTime, start)
+	}
+	if have, want := end, expected.UnixNano(); have != want {
+		t.Errorf("expected end to be %d, got %d", want, have)
+	}
+}
+
+func TestIteratorOptions_Window_MaxTime(t *testing.T) {
+	opt := influxql.IteratorOptions{
+		StartTime: influxql.MinTime,
+		EndTime:   influxql.MaxTime,
+		Interval: influxql.Interval{
+			Duration: time.Hour,
+		},
+	}
+	expected := time.Unix(0, influxql.MaxTime).Truncate(time.Hour)
+
+	start, end := opt.Window(influxql.MaxTime)
+	if have, want := start, expected.UnixNano(); have != want {
+		t.Errorf("expected start to be %d, got %d", want, have)
+	}
+	if end != influxql.MaxTime {
+		t.Errorf("expected end to be %d, got %d", influxql.MaxTime, end)
+	}
+}
+
 func TestIteratorOptions_SeekTime_Ascending(t *testing.T) {
 	opt := influxql.IteratorOptions{
 		StartTime: 30,