fix: memstats new stat should reuse measurement (#516)

rudderlabs · Jun 5, 2024 · ab7c8f6 · ab7c8f6
1 parent 1441aae
commit ab7c8f6
Show file tree

Hide file tree

Showing 2 changed files with 22 additions and 0 deletions.
diff --git a/stats/memstats/stats.go b/stats/memstats/stats.go
@@ -258,6 +258,10 @@ func (ms *Store) NewSampledTaggedStat(name, statType string, tags stats.Tags) st
 	ms.mu.Lock()
 	defer ms.mu.Unlock()
 
+	if m, found := ms.byKey[ms.getKey(name, tags)]; found {
+		return m
+	}
+
 	m := &Measurement{
 		name:  name,
 		tags:  tags,

diff --git a/stats/memstats/stats_test.go b/stats/memstats/stats_test.go
@@ -391,4 +391,22 @@ func TestStats(t *testing.T) {
 		// checking hierarchy
 		require.Equal(t, spans[1].SpanContext.SpanID, spans[0].Parent.SpanID)
 	})
+
+	t.Run("multiple stats with same name and tags", func(t *testing.T) {
+		store, err := memstats.New()
+		require.NoError(t, err)
+
+		name := "testHistogram"
+		store.NewTaggedStat(name, stats.HistogramType, commonTags).Observe(1.0)
+		store.NewTaggedStat(name, stats.HistogramType, commonTags).Observe(2.0)
+
+		require.Equal(t, 2.0, store.Get(name, commonTags).LastValue())
+		require.Equal(t, []float64{1.0, 2.0}, store.Get(name, commonTags).Values())
+
+		require.Equal(t, []memstats.Metric{{
+			Name:   name,
+			Tags:   commonTags,
+			Values: []float64{1.0, 2.0},
+		}}, store.GetByName(name))
+	})
 }