Fix data alignment on the backend

pkg/datasource/response_handler.go

@@ -234,7 +234,7 @@ func getTrendPointValue(point zabbix.TrendPoint, valueType string) (float64, err
 	return 0, fmt.Errorf("failed to get trend value, unknown value type: %s", valueType)
 }
 
-var fixedUpdateIntervalPattern = regexp.MustCompile(`^(\d+)([shd]?)$`)
+var fixedUpdateIntervalPattern = regexp.MustCompile(`^(\d+)([smhdw]?)$`)
 
 func parseItemUpdateInterval(delay string) *time.Duration {
 	if valid := fixedUpdateIntervalPattern.MatchString(delay); !valid {

pkg/datasource/zabbix.go

@@ -100,39 +100,7 @@ func (ds *ZabbixDatasourceInstance) queryNumericDataForItems(ctx context.Context
 	}
 
 	series := convertHistoryToTimeSeries(history, items)
-
-	// Align time series data if possible
-	useTrend := ds.isUseTrend(query.TimeRange)
-	if !query.Options.DisableDataAlignment && !ds.Settings.DisableDataAlignment && !useTrend {
-		for _, s := range series {
-			if s.Meta.Interval != nil {
-				s.TS = s.TS.Align(*s.Meta.Interval)
-			}
-		}
-	}
-
-	series, err = applyFunctions(series, query.Functions)
-	if err != nil {
-		return nil, err
-	}
-
-	for _, s := range series {
-		if int64(s.Len()) > query.MaxDataPoints && query.Interval > 0 {
-			downsampleFunc := consolidateBy
-			if downsampleFunc == "" {
-				downsampleFunc = "avg"
-			}
-			downsampled, err := applyGroupBy(s.TS, query.Interval.String(), downsampleFunc)
-			if err == nil {
-				s.TS = downsampled
-			} else {
-				ds.logger.Debug("Error downsampling series", "error", err)
-			}
-		}
-	}
-
-	frames := convertTimeSeriesToDataFrames(series)
-	return frames, nil
+	return ds.applyDataProcessing(ctx, query, series)
 }
 
 func (ds *ZabbixDatasourceInstance) applyDataProcessing(ctx context.Context, query *QueryModel, series []*timeseries.TimeSeriesData) ([]*data.Frame, error) {
@@ -140,13 +108,21 @@ func (ds *ZabbixDatasourceInstance) applyDataProcessing(ctx context.Context, que
 
 	// Align time series data if possible
 	useTrend := ds.isUseTrend(query.TimeRange)
-	if !query.Options.DisableDataAlignment && !ds.Settings.DisableDataAlignment && !useTrend {
+	disableDataAlignment := query.Options.DisableDataAlignment || ds.Settings.DisableDataAlignment
+	if !disableDataAlignment {
+		if useTrend {
+			for _, s := range series {
+				// Trend data is already aligned (by 1 hour interval), but null values should be added
+				s.TS = s.TS.FillTrendWithNulls()
+			}
+		} else {
 			for _, s := range series {
 				if s.Meta.Interval != nil {
 					s.TS = s.TS.Align(*s.Meta.Interval)
 				}
 			}
 		}
+	}
 
 	series, err := applyFunctions(series, query.Functions)
 	if err != nil {

pkg/timeseries/align.go

@@ -35,6 +35,36 @@ func (ts TimeSeries) Align(interval time.Duration) TimeSeries {
 	return alignedTs
 }
 
+// Fill missing points in trend by null values
+func (ts TimeSeries) FillTrendWithNulls() TimeSeries {
+	if ts.Len() < 2 {
+		return ts
+	}
+
+	interval := time.Hour
+	alignedTs := NewTimeSeries()
+	var frameTs = ts[0].GetTimeFrame(interval)
+	var pointFrameTs time.Time
+	var point TimePoint
+
+	for i := 0; i < ts.Len(); i++ {
+		point = ts[i]
+		pointFrameTs = point.GetTimeFrame(interval)
+
+		if pointFrameTs.After(frameTs) {
+			for frameTs.Before(pointFrameTs) {
+				alignedTs = append(alignedTs, TimePoint{Time: frameTs, Value: nil})
+				frameTs = frameTs.Add(interval)
+			}
+		}
+
+		alignedTs = append(alignedTs, point)
+		frameTs = frameTs.Add(interval)
+	}
+
+	return alignedTs
+}
+
 // Detects interval between data points in milliseconds based on median delta between points.
 func (ts TimeSeries) DetectInterval() time.Duration {
 	if ts.Len() < 2 {