gistfile1.txt

diff --git a/app/vmalert/rule/alerting.go b/app/vmalert/rule/alerting.go
index 07ccce0e4c..2a9695bbfc 100644
--- a/app/vmalert/rule/alerting.go
+++ b/app/vmalert/rule/alerting.go
@@ -425,17 +425,36 @@ func (ar *AlertingRule) exec(ctx context.Context, ts time.Time, limit int) ([]pr
 	// template labels and annotations before updating ar.alerts,
 	// since they could use `query` function which takes a while to execute,
 	// see https://github.com/VictoriaMetrics/VictoriaMetrics/issues/6079.
-	expandedLabels := make([]*labelSet, len(res.Data))
-	expandedAnnotations := make([]map[string]string, len(res.Data))
-	for i, m := range res.Data {
-		ls, as, err := ar.expandTemplates(m, qFn, ts)
+	type alertMetadata struct {
+		value       float64
+		labels      *labelSet
+		annotations map[string]string
+	}
+	ams := make(map[uint64]*alertMetadata, len(res.Data))
+	ar.alertsMu.RLock()
+	for _, m := range res.Data {
+		ls, err := ar.toLabels(m, qFn)
+		if err != nil {
+			curState.Err = fmt.Errorf("failed to expand labels: %w", err)
+			return nil, curState.Err
+		}
+		alertID := hash(ls.processed)
+		activeAt := ts
+		if a, ok := ar.alerts[alertID]; ok {
+			activeAt = a.ActiveAt
+		}
+		as, err := ar.expandTemplates(m, ls, qFn, activeAt)
 		if err != nil {
-			curState.Err = fmt.Errorf("failed to expand templates: %w", err)
+			curState.Err = fmt.Errorf("failed to expand annotations: %w", err)
 			return nil, curState.Err
 		}
-		expandedLabels[i] = ls
-		expandedAnnotations[i] = as
+		ams[alertID] = &alertMetadata{
+			value:       m.Values[0],
+			labels:      ls,
+			annotations: as,
+		}
 	}
+	ar.alertsMu.RUnlock()
 
 	ar.alertsMu.Lock()
 	defer ar.alertsMu.Unlock()
@@ -450,9 +469,8 @@ func (ar *AlertingRule) exec(ctx context.Context, ts time.Time, limit int) ([]pr
 
 	updated := make(map[uint64]struct{})
 	// update list of active alerts
-	for i, m := range res.Data {
-		labels, annotations := expandedLabels[i], expandedAnnotations[i]
-		alertID := hash(labels.processed)
+	for alertID, metadata := range ams {
+		labels, annotations := metadata.labels, metadata.annotations
 		if _, ok := updated[alertID]; ok {
 			// duplicate may be caused the removal of `__name__` label
 			curState.Err = fmt.Errorf("labels %v: %w", labels.processed, errDuplicate)
@@ -468,12 +486,12 @@ func (ar *AlertingRule) exec(ctx context.Context, ts time.Time, limit int) ([]pr
 				a.ActiveAt = ts
 				ar.logDebugf(ts, a, "INACTIVE => PENDING")
 			}
-			a.Value = m.Values[0]
+			a.Value = metadata.value
 			a.Annotations = annotations
 			a.KeepFiringSince = time.Time{}
 			continue
 		}
-		a := ar.newAlert(m, ts, labels.processed, annotations)
+		a := ar.newAlert(metadata.value, ts, labels.processed, annotations)
 		a.ID = alertID
 		a.State = notifier.StatePending
 		ar.alerts[alertID] = a
@@ -536,12 +554,7 @@ func (ar *AlertingRule) exec(ctx context.Context, ts time.Time, limit int) ([]pr
 	return append(tss, ar.toTimeSeries(ts.Unix())...), nil
 }
 
-func (ar *AlertingRule) expandTemplates(m datasource.Metric, qFn templates.QueryFn, ts time.Time) (*labelSet, map[string]string, error) {
-	ls, err := ar.toLabels(m, qFn)
-	if err != nil {
-		return nil, nil, fmt.Errorf("failed to expand labels: %w", err)
-	}
-
+func (ar *AlertingRule) expandTemplates(m datasource.Metric, ls *labelSet, qFn templates.QueryFn, activeAt time.Time) (map[string]string, error) {
 	tplData := notifier.AlertTplData{
 		Value:    m.Values[0],
 		Type:     ar.Type.String(),
@@ -549,14 +562,14 @@ func (ar *AlertingRule) expandTemplates(m datasource.Metric, qFn templates.Query
 		Expr:     ar.Expr,
 		AlertID:  hash(ls.processed),
 		GroupID:  ar.GroupID,
-		ActiveAt: ts,
+		ActiveAt: activeAt,
 		For:      ar.For,
 	}
 	as, err := notifier.ExecTemplate(qFn, ar.Annotations, tplData)
 	if err != nil {
-		return nil, nil, fmt.Errorf("failed to template annotations: %w", err)
+		return nil, fmt.Errorf("failed to template annotations: %w", err)
 	}
-	return ls, as, nil
+	return as, nil
 }
 
 // toTimeSeries creates `ALERTS` and `ALERTS_FOR_STATE` for active alerts
@@ -593,7 +606,7 @@ func hash(labels map[string]string) uint64 {
 	return hash.Sum64()
 }
 
-func (ar *AlertingRule) newAlert(m datasource.Metric, start time.Time, labels, annotations map[string]string) *notifier.Alert {
+func (ar *AlertingRule) newAlert(v float64, start time.Time, labels, annotations map[string]string) *notifier.Alert {
 	as := make(map[string]string)
 	if annotations != nil {
 		as = annotations
@@ -609,7 +622,7 @@ func (ar *AlertingRule) newAlert(m datasource.Metric, start time.Time, labels, a
 		Expr:        ar.Expr,
 		For:         ar.For,
 		ActiveAt:    start,
-		Value:       m.Values[0],
+		Value:       v,
 		Labels:      ls,
 		Annotations: as,
 	}