From a0c22a68305997b91e8a6b3f2a3d29ec1ef8d288 Mon Sep 17 00:00:00 2001
From: Aliaksandr Valialkin <valyala@gmail.com>
Date: Wed, 19 Jun 2019 18:36:47 +0300
Subject: [PATCH] app/vmstorage: add
 `vm_cache_entries{type="storage/hour_metric_ids"}` metric for tracking active
 time series count

---
 app/vmstorage/main.go  |  3 +++
 lib/storage/storage.go | 10 ++++++++++
 2 files changed, 13 insertions(+)

diff --git a/app/vmstorage/main.go b/app/vmstorage/main.go
index 7935e5b060..511207d553 100644
--- a/app/vmstorage/main.go
+++ b/app/vmstorage/main.go
@@ -312,6 +312,9 @@ func registerStorageMetrics(strg *storage.Storage) {
 	metrics.NewGauge(`vm_cache_entries{type="storage/date_metricID"}`, func() float64 {
 		return float64(m().DateMetricIDCacheSize)
 	})
+	metrics.NewGauge(`vm_cache_entries{type="storage/hour_metric_ids"}`, func() float64 {
+		return float64(m().HourMetricIDCacheSize)
+	})
 	metrics.NewGauge(`vm_cache_entries{type="storage/bigIndexBlocks"}`, func() float64 {
 		return float64(tm().BigIndexBlocksCacheSize)
 	})
diff --git a/lib/storage/storage.go b/lib/storage/storage.go
index 85ea1cc2d2..5c2bb828a0 100644
--- a/lib/storage/storage.go
+++ b/lib/storage/storage.go
@@ -295,6 +295,8 @@ type Metrics struct {
 	DateMetricIDCacheMisses     uint64
 	DateMetricIDCacheCollisions uint64
 
+	HourMetricIDCacheSize uint64
+
 	IndexDBMetrics IndexDBMetrics
 	TableMetrics   TableMetrics
 }
@@ -338,6 +340,14 @@ func (s *Storage) UpdateMetrics(m *Metrics) {
 	m.DateMetricIDCacheMisses += cs.Misses
 	m.DateMetricIDCacheCollisions += cs.Collisions
 
+	hmCurr := s.currHourMetricIDs.Load().(*hourMetricIDs)
+	hmPrev := s.prevHourMetricIDs.Load().(*hourMetricIDs)
+	hourMetricIDsLen := len(hmPrev.m)
+	if len(hmCurr.m) > hourMetricIDsLen {
+		hourMetricIDsLen = len(hmCurr.m)
+	}
+	m.HourMetricIDCacheSize += uint64(hourMetricIDsLen)
+
 	s.idb().UpdateMetrics(&m.IndexDBMetrics)
 	s.tb.UpdateMetrics(&m.TableMetrics)
 }