Chore: Reduce TSDB Go code complexity (#26401)

* tsdb: Make code less complex

pkg/tsdb/cloudmonitoring/cloudmonitoring.go

@@ -502,11 +502,43 @@ func (e *CloudMonitoringExecutor) unmarshalResponse(res *http.Response) (cloudMo
 	return data, nil
 }
 
+func handleDistributionSeries(series timeSeries, defaultMetricName string, seriesLabels map[string]string,
+	query *cloudMonitoringQuery, queryRes *tsdb.QueryResult) {
+	points := make([]tsdb.TimePoint, 0)
+	for i := len(series.Points) - 1; i >= 0; i-- {
+		point := series.Points[i]
+		value := point.Value.DoubleValue
+
+		if series.ValueType == "INT64" {
+			parsedValue, err := strconv.ParseFloat(point.Value.IntValue, 64)
+			if err == nil {
+				value = parsedValue
+			}
+		}
+
+		if series.ValueType == "BOOL" {
+			if point.Value.BoolValue {
+				value = 1
+			} else {
+				value = 0
+			}
+		}
+
+		points = append(points, tsdb.NewTimePoint(null.FloatFrom(value), float64((point.Interval.EndTime).Unix())*1000))
+	}
+
+	metricName := formatLegendKeys(series.Metric.Type, defaultMetricName, seriesLabels, nil, query)
+
+	queryRes.Series = append(queryRes.Series, &tsdb.TimeSeries{
+		Name:   metricName,
+		Points: points,
+	})
+}
+
 func (e *CloudMonitoringExecutor) parseResponse(queryRes *tsdb.QueryResult, data cloudMonitoringResponse, query *cloudMonitoringQuery) error {
 	labels := make(map[string]map[string]bool)
 
 	for _, series := range data.TimeSeries {
-		points := make([]tsdb.TimePoint, 0)
 		seriesLabels := make(map[string]string)
 		defaultMetricName := series.Metric.Type
 		labels["resource.type"] = map[string]bool{series.Resource.Type: true}
@@ -566,34 +598,7 @@ func (e *CloudMonitoringExecutor) parseResponse(queryRes *tsdb.QueryResult, data
 
 		// reverse the order to be ascending
 		if series.ValueType != "DISTRIBUTION" {
-			for i := len(series.Points) - 1; i >= 0; i-- {
-				point := series.Points[i]
-				value := point.Value.DoubleValue
-
-				if series.ValueType == "INT64" {
-					parsedValue, err := strconv.ParseFloat(point.Value.IntValue, 64)
-					if err == nil {
-						value = parsedValue
-					}
-				}
-
-				if series.ValueType == "BOOL" {
-					if point.Value.BoolValue {
-						value = 1
-					} else {
-						value = 0
-					}
-				}
-
-				points = append(points, tsdb.NewTimePoint(null.FloatFrom(value), float64((point.Interval.EndTime).Unix())*1000))
-			}
-
-			metricName := formatLegendKeys(series.Metric.Type, defaultMetricName, seriesLabels, nil, query)
-
-			queryRes.Series = append(queryRes.Series, &tsdb.TimeSeries{
-				Name:   metricName,
-				Points: points,
-			})
+			handleDistributionSeries(series, defaultMetricName, seriesLabels, query, queryRes)
 		} else {
 			buckets := make(map[int]*tsdb.TimeSeries)
 

pkg/tsdb/cloudmonitoring/types.go

@@ -65,46 +65,48 @@ type (
 	}
 
 	cloudMonitoringResponse struct {
-		TimeSeries []struct {
-			Metric struct {
-				Labels map[string]string `json:"labels"`
-				Type   string            `json:"type"`
-			} `json:"metric"`
-			Resource struct {
-				Type   string            `json:"type"`
-				Labels map[string]string `json:"labels"`
-			} `json:"resource"`
-			MetaData   map[string]map[string]interface{} `json:"metadata"`
-			MetricKind string                            `json:"metricKind"`
-			ValueType  string                            `json:"valueType"`
-			Points     []struct {
-				Interval struct {
-					StartTime time.Time `json:"startTime"`
-					EndTime   time.Time `json:"endTime"`
-				} `json:"interval"`
-				Value struct {
-					DoubleValue       float64 `json:"doubleValue"`
-					StringValue       string  `json:"stringValue"`
-					BoolValue         bool    `json:"boolValue"`
-					IntValue          string  `json:"int64Value"`
-					DistributionValue struct {
-						Count                 string  `json:"count"`
-						Mean                  float64 `json:"mean"`
-						SumOfSquaredDeviation float64 `json:"sumOfSquaredDeviation"`
-						Range                 struct {
-							Min int `json:"min"`
-							Max int `json:"max"`
-						} `json:"range"`
-						BucketOptions cloudMonitoringBucketOptions `json:"bucketOptions"`
-						BucketCounts  []string                     `json:"bucketCounts"`
-						Examplars     []struct {
-							Value     float64 `json:"value"`
-							Timestamp string  `json:"timestamp"`
-							// attachments
-						} `json:"examplars"`
-					} `json:"distributionValue"`
-				} `json:"value"`
-			} `json:"points"`
-		} `json:"timeSeries"`
+		TimeSeries []timeSeries `json:"timeSeries"`
 	}
 )
+
+type timeSeries struct {
+	Metric struct {
+		Labels map[string]string `json:"labels"`
+		Type   string            `json:"type"`
+	} `json:"metric"`
+	Resource struct {
+		Type   string            `json:"type"`
+		Labels map[string]string `json:"labels"`
+	} `json:"resource"`
+	MetaData   map[string]map[string]interface{} `json:"metadata"`
+	MetricKind string                            `json:"metricKind"`
+	ValueType  string                            `json:"valueType"`
+	Points     []struct {
+		Interval struct {
+			StartTime time.Time `json:"startTime"`
+			EndTime   time.Time `json:"endTime"`
+		} `json:"interval"`
+		Value struct {
+			DoubleValue       float64 `json:"doubleValue"`
+			StringValue       string  `json:"stringValue"`
+			BoolValue         bool    `json:"boolValue"`
+			IntValue          string  `json:"int64Value"`
+			DistributionValue struct {
+				Count                 string  `json:"count"`
+				Mean                  float64 `json:"mean"`
+				SumOfSquaredDeviation float64 `json:"sumOfSquaredDeviation"`
+				Range                 struct {
+					Min int `json:"min"`
+					Max int `json:"max"`
+				} `json:"range"`
+				BucketOptions cloudMonitoringBucketOptions `json:"bucketOptions"`
+				BucketCounts  []string                     `json:"bucketCounts"`
+				Examplars     []struct {
+					Value     float64 `json:"value"`
+					Timestamp string  `json:"timestamp"`
+					// attachments
+				} `json:"examplars"`
+			} `json:"distributionValue"`
+		} `json:"value"`
+	} `json:"points"`
+}

pkg/tsdb/elasticsearch/time_series_query.go

@@ -24,9 +24,6 @@ var newTimeSeriesQuery = func(client es.Client, tsdbQuery *tsdb.TsdbQuery, inter
 }
 
 func (e *timeSeriesQuery) execute() (*tsdb.Response, error) {
-	result := &tsdb.Response{}
-	result.Results = make(map[string]*tsdb.QueryResult)
-
 	tsQueryParser := newTimeSeriesQueryParser()
 	queries, err := tsQueryParser.parse(e.tsdbQuery)
 	if err != nil {
@@ -37,121 +34,13 @@ func (e *timeSeriesQuery) execute() (*tsdb.Response, error) {
 
 	from := fmt.Sprintf("%d", e.tsdbQuery.TimeRange.GetFromAsMsEpoch())
 	to := fmt.Sprintf("%d", e.tsdbQuery.TimeRange.GetToAsMsEpoch())
-
+	result := &tsdb.Response{
+		Results: make(map[string]*tsdb.QueryResult),
+	}
 	for _, q := range queries {
-		minInterval, err := e.client.GetMinInterval(q.Interval)
-		if err != nil {
+		if err := e.processQuery(q, ms, from, to, result); err != nil {
 			return nil, err
 		}
-		interval := e.intervalCalculator.Calculate(e.tsdbQuery.TimeRange, minInterval)
-
-		b := ms.Search(interval)
-		b.Size(0)
-		filters := b.Query().Bool().Filter()
-		filters.AddDateRangeFilter(e.client.GetTimeField(), to, from, es.DateFormatEpochMS)
-
-		if q.RawQuery != "" {
-			filters.AddQueryStringFilter(q.RawQuery, true)
-		}
-
-		if len(q.BucketAggs) == 0 {
-			if len(q.Metrics) == 0 || q.Metrics[0].Type != "raw_document" {
-				result.Results[q.RefID] = &tsdb.QueryResult{
-					RefId:       q.RefID,
-					Error:       fmt.Errorf("invalid query, missing metrics and aggregations"),
-					ErrorString: "invalid query, missing metrics and aggregations",
-				}
-				continue
-			}
-			metric := q.Metrics[0]
-			b.Size(metric.Settings.Get("size").MustInt(500))
-			b.SortDesc("@timestamp", "boolean")
-			b.AddDocValueField("@timestamp")
-			continue
-		}
-
-		aggBuilder := b.Agg()
-
-		// iterate backwards to create aggregations bottom-down
-		for _, bucketAgg := range q.BucketAggs {
-			switch bucketAgg.Type {
-			case dateHistType:
-				aggBuilder = addDateHistogramAgg(aggBuilder, bucketAgg, from, to)
-			case histogramType:
-				aggBuilder = addHistogramAgg(aggBuilder, bucketAgg)
-			case filtersType:
-				aggBuilder = addFiltersAgg(aggBuilder, bucketAgg)
-			case termsType:
-				aggBuilder = addTermsAgg(aggBuilder, bucketAgg, q.Metrics)
-			case geohashGridType:
-				aggBuilder = addGeoHashGridAgg(aggBuilder, bucketAgg)
-			}
-		}
-
-		for _, m := range q.Metrics {
-			m := m
-			if m.Type == countType {
-				continue
-			}
-
-			if isPipelineAgg(m.Type) {
-				if isPipelineAggWithMultipleBucketPaths(m.Type) {
-					if len(m.PipelineVariables) > 0 {
-						bucketPaths := map[string]interface{}{}
-						for name, pipelineAgg := range m.PipelineVariables {
-							if _, err := strconv.Atoi(pipelineAgg); err == nil {
-								var appliedAgg *MetricAgg
-								for _, pipelineMetric := range q.Metrics {
-									if pipelineMetric.ID == pipelineAgg {
-										appliedAgg = pipelineMetric
-										break
-									}
-								}
-								if appliedAgg != nil {
-									if appliedAgg.Type == countType {
-										bucketPaths[name] = "_count"
-									} else {
-										bucketPaths[name] = pipelineAgg
-									}
-								}
-							}
-						}
-
-						aggBuilder.Pipeline(m.ID, m.Type, bucketPaths, func(a *es.PipelineAggregation) {
-							a.Settings = m.Settings.MustMap()
-						})
-					} else {
-						continue
-					}
-				} else {
-					if _, err := strconv.Atoi(m.PipelineAggregate); err == nil {
-						var appliedAgg *MetricAgg
-						for _, pipelineMetric := range q.Metrics {
-							if pipelineMetric.ID == m.PipelineAggregate {
-								appliedAgg = pipelineMetric
-								break
-							}
-						}
-						if appliedAgg != nil {
-							bucketPath := m.PipelineAggregate
-							if appliedAgg.Type == countType {
-								bucketPath = "_count"
-							}
-
-							aggBuilder.Pipeline(m.ID, m.Type, bucketPath, func(a *es.PipelineAggregation) {
-								a.Settings = m.Settings.MustMap()
-							})
-						}
-					} else {
-						continue
-					}
-				}
-			} else {
-				aggBuilder.Metric(m.ID, m.Type, m.Field, func(a *es.MetricAggregation) {
-					a.Settings = m.Settings.MustMap()
-				})
-			}
-		}
 	}
 
 	req, err := ms.Build()
@@ -168,6 +57,125 @@ func (e *timeSeriesQuery) execute() (*tsdb.Response, error) {
 	return rp.getTimeSeries()
 }
 
+func (e *timeSeriesQuery) processQuery(q *Query, ms *es.MultiSearchRequestBuilder, from, to string,
+	result *tsdb.Response) error {
+	minInterval, err := e.client.GetMinInterval(q.Interval)
+	if err != nil {
+		return err
+	}
+	interval := e.intervalCalculator.Calculate(e.tsdbQuery.TimeRange, minInterval)
+
+	b := ms.Search(interval)
+	b.Size(0)
+	filters := b.Query().Bool().Filter()
+	filters.AddDateRangeFilter(e.client.GetTimeField(), to, from, es.DateFormatEpochMS)
+
+	if q.RawQuery != "" {
+		filters.AddQueryStringFilter(q.RawQuery, true)
+	}
+
+	if len(q.BucketAggs) == 0 {
+		if len(q.Metrics) == 0 || q.Metrics[0].Type != "raw_document" {
+			result.Results[q.RefID] = &tsdb.QueryResult{
+				RefId:       q.RefID,
+				Error:       fmt.Errorf("invalid query, missing metrics and aggregations"),
+				ErrorString: "invalid query, missing metrics and aggregations",
+			}
+			return nil
+		}
+		metric := q.Metrics[0]
+		b.Size(metric.Settings.Get("size").MustInt(500))
+		b.SortDesc("@timestamp", "boolean")
+		b.AddDocValueField("@timestamp")
+		return nil
+	}
+
+	aggBuilder := b.Agg()
+
+	// iterate backwards to create aggregations bottom-down
+	for _, bucketAgg := range q.BucketAggs {
+		switch bucketAgg.Type {
+		case dateHistType:
+			aggBuilder = addDateHistogramAgg(aggBuilder, bucketAgg, from, to)
+		case histogramType:
+			aggBuilder = addHistogramAgg(aggBuilder, bucketAgg)
+		case filtersType:
+			aggBuilder = addFiltersAgg(aggBuilder, bucketAgg)
+		case termsType:
+			aggBuilder = addTermsAgg(aggBuilder, bucketAgg, q.Metrics)
+		case geohashGridType:
+			aggBuilder = addGeoHashGridAgg(aggBuilder, bucketAgg)
+		}
+	}
+
+	for _, m := range q.Metrics {
+		m := m
+		if m.Type == countType {
+			continue
+		}
+
+		if isPipelineAgg(m.Type) {
+			if isPipelineAggWithMultipleBucketPaths(m.Type) {
+				if len(m.PipelineVariables) > 0 {
+					bucketPaths := map[string]interface{}{}
+					for name, pipelineAgg := range m.PipelineVariables {
+						if _, err := strconv.Atoi(pipelineAgg); err == nil {
+							var appliedAgg *MetricAgg
+							for _, pipelineMetric := range q.Metrics {
+								if pipelineMetric.ID == pipelineAgg {
+									appliedAgg = pipelineMetric
+									break
+								}
+							}
+							if appliedAgg != nil {
+								if appliedAgg.Type == countType {
+									bucketPaths[name] = "_count"
+								} else {
+									bucketPaths[name] = pipelineAgg
+								}
+							}
+						}
+					}
+
+					aggBuilder.Pipeline(m.ID, m.Type, bucketPaths, func(a *es.PipelineAggregation) {
+						a.Settings = m.Settings.MustMap()
+					})
+				} else {
+					continue
+				}
+			} else {
+				if _, err := strconv.Atoi(m.PipelineAggregate); err == nil {
+					var appliedAgg *MetricAgg
+					for _, pipelineMetric := range q.Metrics {
+						if pipelineMetric.ID == m.PipelineAggregate {
+							appliedAgg = pipelineMetric
+							break
+						}
+					}
+					if appliedAgg != nil {
+						bucketPath := m.PipelineAggregate
+						if appliedAgg.Type == countType {
+							bucketPath = "_count"
+						}
+
+						aggBuilder.Pipeline(m.ID, m.Type, bucketPath, func(a *es.PipelineAggregation) {
+							a.Settings = m.Settings.MustMap()
+						})
+					}
+				} else {
+					continue
+				}
+			}
+		} else {
+			aggBuilder.Metric(m.ID, m.Type, m.Field, func(a *es.MetricAggregation) {
+				a.Settings = m.Settings.MustMap()
+			})
+		}
+	}
+
+	return nil
+}
+
 func addDateHistogramAgg(aggBuilder es.AggBuilder, bucketAgg *BucketAgg, timeFrom, timeTo string) es.AggBuilder {
 	aggBuilder.DateHistogram(bucketAgg.ID, bucketAgg.Field, func(a *es.DateHistogramAgg, b es.AggBuilder) {
 		a.Interval = bucketAgg.Settings.Get("interval").MustString("auto")

pkg/tsdb/sqleng/sql_engine.go

@@ -276,45 +276,60 @@ func (e *sqlQueryEndpoint) transformToTable(query *tsdb.Query, rows *core.Rows,
 	return nil
 }
 
-func (e *sqlQueryEndpoint) transformToTimeSeries(query *tsdb.Query, rows *core.Rows, result *tsdb.QueryResult, tsdbQuery *tsdb.TsdbQuery) error {
-	pointsBySeries := make(map[string]*tsdb.TimeSeries)
-	seriesByQueryOrder := list.New()
-
+func newProcessCfg(query *tsdb.Query, tsdbQuery *tsdb.TsdbQuery, rows *core.Rows) (*processCfg, error) {
 	columnNames, err := rows.Columns()
 	if err != nil {
-		return err
+		return nil, err
+	}
+	columnTypes, err := rows.ColumnTypes()
+	if err != nil {
+		return nil, err
 	}
 
-	columnTypes, err := rows.ColumnTypes()
+	fillMissing := query.Model.Get("fill").MustBool(false)
+
+	cfg := &processCfg{
+		rowCount:           0,
+		columnTypes:        columnTypes,
+		columnNames:        columnNames,
+		rows:               rows,
+		timeIndex:          -1,
+		metricIndex:        -1,
+		metricPrefix:       false,
+		fillMissing:        fillMissing,
+		seriesByQueryOrder: list.New(),
+		pointsBySeries:     make(map[string]*tsdb.TimeSeries),
+		tsdbQuery:          tsdbQuery,
+	}
+	return cfg, nil
+}
+
+func (e *sqlQueryEndpoint) transformToTimeSeries(query *tsdb.Query, rows *core.Rows, result *tsdb.QueryResult,
+	tsdbQuery *tsdb.TsdbQuery) error {
+	cfg, err := newProcessCfg(query, tsdbQuery, rows)
 	if err != nil {
 		return err
 	}
 
-	rowCount := 0
-	timeIndex := -1
-	metricIndex := -1
-	metricPrefix := false
-	var metricPrefixValue string
-
 	// check columns of resultset: a column named time is mandatory
 	// the first text column is treated as metric name unless a column named metric is present
-	for i, col := range columnNames {
+	for i, col := range cfg.columnNames {
 		for _, tc := range e.timeColumnNames {
 			if col == tc {
-				timeIndex = i
+				cfg.timeIndex = i
 				continue
 			}
 		}
 		switch col {
 		case "metric":
-			metricIndex = i
+			cfg.metricIndex = i
 		default:
-			if metricIndex == -1 {
-				columnType := columnTypes[i].DatabaseTypeName()
+			if cfg.metricIndex == -1 {
+				columnType := cfg.columnTypes[i].DatabaseTypeName()
 
 				for _, mct := range e.metricColumnTypes {
 					if columnType == mct {
-						metricIndex = i
+						cfg.metricIndex = i
 						continue
 					}
 				}
@@ -323,154 +338,179 @@ func (e *sqlQueryEndpoint) transformToTimeSeries(query *tsdb.Query, rows *core.R
 	}
 
 	// use metric column as prefix with multiple value columns
-	if metricIndex != -1 && len(columnNames) > 3 {
-		metricPrefix = true
+	if cfg.metricIndex != -1 && len(cfg.columnNames) > 3 {
+		cfg.metricPrefix = true
 	}
 
-	if timeIndex == -1 {
+	if cfg.timeIndex == -1 {
 		return fmt.Errorf("Found no column named %s", strings.Join(e.timeColumnNames, " or "))
 	}
 
-	fillMissing := query.Model.Get("fill").MustBool(false)
-	var fillInterval float64
-	fillValue := null.Float{}
-	fillPrevious := false
-
-	if fillMissing {
-		fillInterval = query.Model.Get("fillInterval").MustFloat64() * 1000
+	if cfg.fillMissing {
+		cfg.fillInterval = query.Model.Get("fillInterval").MustFloat64() * 1000
 		switch query.Model.Get("fillMode").MustString() {
 		case "null":
 		case "previous":
-			fillPrevious = true
+			cfg.fillPrevious = true
 		case "value":
-			fillValue.Float64 = query.Model.Get("fillValue").MustFloat64()
-			fillValue.Valid = true
+			cfg.fillValue.Float64 = query.Model.Get("fillValue").MustFloat64()
+			cfg.fillValue.Valid = true
 		}
 	}
 
 	for rows.Next() {
-		var timestamp float64
-		var value null.Float
-		var metric string
-
-		if rowCount > rowLimit {
-			return fmt.Errorf("query row limit exceeded, limit %d", rowLimit)
-		}
-
-		values, err := e.queryResultTransformer.TransformQueryResult(columnTypes, rows)
-		if err != nil {
+		if err := e.processRow(cfg); err != nil {
 			return err
 		}
-
-		// converts column named time to unix timestamp in milliseconds to make
-		// native mysql datetime types and epoch dates work in
-		// annotation and table queries.
-		ConvertSqlTimeColumnToEpochMs(values, timeIndex)
-
-		switch columnValue := values[timeIndex].(type) {
-		case int64:
-			timestamp = float64(columnValue)
-		case float64:
-			timestamp = columnValue
-		default:
-			return fmt.Errorf("Invalid type for column time, must be of type timestamp or unix timestamp, got: %T %v", columnValue, columnValue)
-		}
-
-		if metricIndex >= 0 {
-			if columnValue, ok := values[metricIndex].(string); ok {
-				if metricPrefix {
-					metricPrefixValue = columnValue
-				} else {
-					metric = columnValue
-				}
-			} else {
-				return fmt.Errorf("Column metric must be of type %s. metric column name: %s type: %s but datatype is %T", strings.Join(e.metricColumnTypes, ", "), columnNames[metricIndex], columnTypes[metricIndex].DatabaseTypeName(), values[metricIndex])
-			}
-		}
-
-		for i, col := range columnNames {
-			if i == timeIndex || i == metricIndex {
-				continue
-			}
-
-			if value, err = ConvertSqlValueColumnToFloat(col, values[i]); err != nil {
-				return err
-			}
-
-			if metricIndex == -1 {
-				metric = col
-			} else if metricPrefix {
-				metric = metricPrefixValue + " " + col
-			}
-
-			series, exist := pointsBySeries[metric]
-			if !exist {
-				series = &tsdb.TimeSeries{Name: metric}
-				pointsBySeries[metric] = series
-				seriesByQueryOrder.PushBack(metric)
-			}
-
-			if fillMissing {
-				var intervalStart float64
-				if !exist {
-					intervalStart = float64(tsdbQuery.TimeRange.MustGetFrom().UnixNano() / 1e6)
-				} else {
-					intervalStart = series.Points[len(series.Points)-1][1].Float64 + fillInterval
-				}
-
-				if fillPrevious {
-					if len(series.Points) > 0 {
-						fillValue = series.Points[len(series.Points)-1][0]
-					} else {
-						fillValue.Valid = false
-					}
-				}
-
-				// align interval start
-				intervalStart = math.Floor(intervalStart/fillInterval) * fillInterval
-
-				for i := intervalStart; i < timestamp; i += fillInterval {
-					series.Points = append(series.Points, tsdb.TimePoint{fillValue, null.FloatFrom(i)})
-					rowCount++
-				}
-			}
-
-			series.Points = append(series.Points, tsdb.TimePoint{value, null.FloatFrom(timestamp)})
-
-			if setting.Env == setting.DEV {
-				e.log.Debug("Rows", "metric", metric, "time", timestamp, "value", value)
-			}
-		}
 	}
 
-	for elem := seriesByQueryOrder.Front(); elem != nil; elem = elem.Next() {
+	for elem := cfg.seriesByQueryOrder.Front(); elem != nil; elem = elem.Next() {
 		key := elem.Value.(string)
-		result.Series = append(result.Series, pointsBySeries[key])
+		result.Series = append(result.Series, cfg.pointsBySeries[key])
+		if !cfg.fillMissing {
+			continue
+		}
 
-		if fillMissing {
-			series := pointsBySeries[key]
-			// fill in values from last fetched value till interval end
-			intervalStart := series.Points[len(series.Points)-1][1].Float64
-			intervalEnd := float64(tsdbQuery.TimeRange.MustGetTo().UnixNano() / 1e6)
+		series := cfg.pointsBySeries[key]
+		// fill in values from last fetched value till interval end
+		intervalStart := series.Points[len(series.Points)-1][1].Float64
+		intervalEnd := float64(tsdbQuery.TimeRange.MustGetTo().UnixNano() / 1e6)
 
-			if fillPrevious {
+		if cfg.fillPrevious {
+			if len(series.Points) > 0 {
+				cfg.fillValue = series.Points[len(series.Points)-1][0]
+			} else {
+				cfg.fillValue.Valid = false
+			}
+		}
+
+		// align interval start
+		intervalStart = math.Floor(intervalStart/cfg.fillInterval) * cfg.fillInterval
+		for i := intervalStart + cfg.fillInterval; i < intervalEnd; i += cfg.fillInterval {
+			series.Points = append(series.Points, tsdb.TimePoint{cfg.fillValue, null.FloatFrom(i)})
+			cfg.rowCount++
+		}
+	}
+
+	result.Meta.Set("rowCount", cfg.rowCount)
+	return nil
+}
+
+type processCfg struct {
+	rowCount           int
+	columnTypes        []*sql.ColumnType
+	columnNames        []string
+	rows               *core.Rows
+	timeIndex          int
+	metricIndex        int
+	metricPrefix       bool
+	metricPrefixValue  string
+	fillMissing        bool
+	pointsBySeries     map[string]*tsdb.TimeSeries
+	seriesByQueryOrder *list.List
+	fillValue          null.Float
+	tsdbQuery          *tsdb.TsdbQuery
+	fillInterval       float64
+	fillPrevious       bool
+}
+
+func (e *sqlQueryEndpoint) processRow(cfg *processCfg) error {
+	var timestamp float64
+	var value null.Float
+	var metric string
+
+	if cfg.rowCount > rowLimit {
+		return fmt.Errorf("query row limit exceeded, limit %d", rowLimit)
+	}
+
+	values, err := e.queryResultTransformer.TransformQueryResult(cfg.columnTypes, cfg.rows)
+	if err != nil {
+		return err
+	}
+
+	// converts column named time to unix timestamp in milliseconds to make
+	// native mysql datetime types and epoch dates work in
+	// annotation and table queries.
+	ConvertSqlTimeColumnToEpochMs(values, cfg.timeIndex)
+
+	switch columnValue := values[cfg.timeIndex].(type) {
+	case int64:
+		timestamp = float64(columnValue)
+	case float64:
+		timestamp = columnValue
+	default:
+		return fmt.Errorf("invalid type for column time, must be of type timestamp or unix timestamp, got: %T %v",
+			columnValue, columnValue)
+	}
+
+	if cfg.metricIndex >= 0 {
+		if columnValue, ok := values[cfg.metricIndex].(string); ok {
+			if cfg.metricPrefix {
+				cfg.metricPrefixValue = columnValue
+			} else {
+				metric = columnValue
+			}
+		} else {
+			return fmt.Errorf("column metric must be of type %s. metric column name: %s type: %s but datatype is %T",
+				strings.Join(e.metricColumnTypes, ", "), cfg.columnNames[cfg.metricIndex],
+				cfg.columnTypes[cfg.metricIndex].DatabaseTypeName(), values[cfg.metricIndex])
+		}
+	}
+
+	for i, col := range cfg.columnNames {
+		if i == cfg.timeIndex || i == cfg.metricIndex {
+			continue
+		}
+
+		if value, err = ConvertSqlValueColumnToFloat(col, values[i]); err != nil {
+			return err
+		}
+
+		if cfg.metricIndex == -1 {
+			metric = col
+		} else if cfg.metricPrefix {
+			metric = cfg.metricPrefixValue + " " + col
+		}
+
+		series, exist := cfg.pointsBySeries[metric]
+		if !exist {
+			series = &tsdb.TimeSeries{Name: metric}
+			cfg.pointsBySeries[metric] = series
+			cfg.seriesByQueryOrder.PushBack(metric)
+		}
+
+		if cfg.fillMissing {
+			var intervalStart float64
+			if !exist {
+				intervalStart = float64(cfg.tsdbQuery.TimeRange.MustGetFrom().UnixNano() / 1e6)
+			} else {
+				intervalStart = series.Points[len(series.Points)-1][1].Float64 + cfg.fillInterval
+			}
+
+			if cfg.fillPrevious {
 				if len(series.Points) > 0 {
-					fillValue = series.Points[len(series.Points)-1][0]
+					cfg.fillValue = series.Points[len(series.Points)-1][0]
 				} else {
-					fillValue.Valid = false
+					cfg.fillValue.Valid = false
 				}
 			}
 
 			// align interval start
-			intervalStart = math.Floor(intervalStart/fillInterval) * fillInterval
-			for i := intervalStart + fillInterval; i < intervalEnd; i += fillInterval {
-				series.Points = append(series.Points, tsdb.TimePoint{fillValue, null.FloatFrom(i)})
-				rowCount++
+			intervalStart = math.Floor(intervalStart/cfg.fillInterval) * cfg.fillInterval
+
+			for i := intervalStart; i < timestamp; i += cfg.fillInterval {
+				series.Points = append(series.Points, tsdb.TimePoint{cfg.fillValue, null.FloatFrom(i)})
+				cfg.rowCount++
 			}
 		}
+
+		series.Points = append(series.Points, tsdb.TimePoint{value, null.FloatFrom(timestamp)})
+
+		if setting.Env == setting.DEV {
+			e.log.Debug("Rows", "metric", metric, "time", timestamp, "value", value)
+		}
 	}
 
-	result.Meta.Set("rowCount", rowCount)
 	return nil
 }
 
@@ -526,6 +566,7 @@ func ConvertSqlTimeColumnToEpochMs(values tsdb.RowValues, timeIndex int) {
 }
 
 // ConvertSqlValueColumnToFloat converts timeseries value column to float.
+//nolint: gocyclo
 func ConvertSqlValueColumnToFloat(columnName string, columnValue interface{}) (null.Float, error) {
 	var value null.Float