diff --git a/go.mod b/go.mod
index fb74c1180..3a39d8399 100644
--- a/go.mod
+++ b/go.mod
@@ -4,7 +4,7 @@ require (
 	cloud.google.com/go v0.49.0 // indirect
 	cloud.google.com/go/storage v1.4.0
 	github.com/VictoriaMetrics/fastcache v1.5.4
-	github.com/VictoriaMetrics/metrics v1.9.1
+	github.com/VictoriaMetrics/metrics v1.9.2
 	github.com/aws/aws-sdk-go v1.25.43
 	github.com/cespare/xxhash/v2 v2.1.1
 	github.com/golang/groupcache v0.0.0-20191027212112-611e8accdfc9 // indirect
diff --git a/go.sum b/go.sum
index c78837aa8..158a92363 100644
--- a/go.sum
+++ b/go.sum
@@ -22,8 +22,8 @@ github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
 github.com/VictoriaMetrics/fastcache v1.5.4 h1:0BaXbRH01RycJk79OOBwMCXlNryko9z4yEf6RqbP+Xo=
 github.com/VictoriaMetrics/fastcache v1.5.4/go.mod h1:ptDBkNMQI4RtmVo8VS/XwRY6RoTu1dAWCbrk+6WsEM8=
-github.com/VictoriaMetrics/metrics v1.9.1 h1:6bkFBTSCZ3woLQ6+ZLRIvrYjGn7GDqOid297WiT38o4=
-github.com/VictoriaMetrics/metrics v1.9.1/go.mod h1:LU2j9qq7xqZYXz8tF3/RQnB2z2MbZms5TDiIg9/NHiQ=
+github.com/VictoriaMetrics/metrics v1.9.2 h1:+CNV5OOPe1PuHff3AsOa5cbN8qCWkWwZZA7eOmFjOwQ=
+github.com/VictoriaMetrics/metrics v1.9.2/go.mod h1:LU2j9qq7xqZYXz8tF3/RQnB2z2MbZms5TDiIg9/NHiQ=
 github.com/allegro/bigcache v1.2.1-0.20190218064605-e24eb225f156 h1:eMwmnE/GDgah4HI848JfFxHt+iPb26b4zyfspmqY0/8=
 github.com/allegro/bigcache v1.2.1-0.20190218064605-e24eb225f156/go.mod h1:Cb/ax3seSYIx7SuZdm2G2xzfwmv3TPSk2ucNfQESPXM=
 github.com/aws/aws-sdk-go v1.25.43 h1:R5YqHQFIulYVfgRySz9hvBRTWBjudISa+r0C8XQ1ufg=
diff --git a/vendor/github.com/VictoriaMetrics/metrics/README.md b/vendor/github.com/VictoriaMetrics/metrics/README.md
index 6cb230507..4f1283abb 100644
--- a/vendor/github.com/VictoriaMetrics/metrics/README.md
+++ b/vendor/github.com/VictoriaMetrics/metrics/README.md
@@ -15,6 +15,7 @@
 * Fast.
 * Allows exporting distinct metric sets via distinct endpoints. See [Set](http://godoc.org/github.com/VictoriaMetrics/metrics#Set).
 * Supports [easy-to-use histograms](http://godoc.org/github.com/VictoriaMetrics/metrics#Histogram), which just work without any tuning.
+  Read more about VictoriaMetrics histograms at [this article](https://medium.com/@valyala/improving-histogram-usability-for-prometheus-and-grafana-bc7e5df0e350).
 
 
 ### Limitations
diff --git a/vendor/github.com/VictoriaMetrics/metrics/histogram.go b/vendor/github.com/VictoriaMetrics/metrics/histogram.go
index 2d5f80bfa..6db9b9f83 100644
--- a/vendor/github.com/VictoriaMetrics/metrics/histogram.go
+++ b/vendor/github.com/VictoriaMetrics/metrics/histogram.go
@@ -19,6 +19,8 @@ const (
 
 // Histogram is a histogram for non-negative values with automatically created buckets.
 //
+// See https://medium.com/@valyala/improving-histogram-usability-for-prometheus-and-grafana-bc7e5df0e350
+//
 // Each bucket contains a counter for values in the given range.
 // Each non-empty bucket is exposed via the following metric:
 //
@@ -32,7 +34,8 @@ const (
 //     - <counter> - the number of hits to the given bucket during Update* calls
 //
 // Histogram buckets can be converted to Prometheus-like buckets with `le` labels
-// with `prometheus_buckets(<metric_name>_bucket)` function in VictoriaMetrics:
+// with `prometheus_buckets(<metric_name>_bucket)` function from Extended PromQL in VictoriaMetrics.
+// (see https://github.com/VictoriaMetrics/VictoriaMetrics/wiki/ExtendedPromQL ):
 //
 //     prometheus_buckets(request_duration_bucket)
 //
diff --git a/vendor/github.com/VictoriaMetrics/metrics/set.go b/vendor/github.com/VictoriaMetrics/metrics/set.go
index dfc00426c..15976df75 100644
--- a/vendor/github.com/VictoriaMetrics/metrics/set.go
+++ b/vendor/github.com/VictoriaMetrics/metrics/set.go
@@ -42,10 +42,14 @@ func (s *Set) WritePrometheus(w io.Writer) {
 	if !sort.SliceIsSorted(s.a, lessFunc) {
 		sort.Slice(s.a, lessFunc)
 	}
-	for _, nm := range s.a {
+	sa := append([]*namedMetric(nil), s.a...)
+	s.mu.Unlock()
+
+	// Call marshalTo without the global lock, since certain metric types such as Gauge
+	// can call a callback, which, in turn, can try calling s.mu.Lock again.
+	for _, nm := range sa {
 		nm.metric.marshalTo(nm.name, &bb)
 	}
-	s.mu.Unlock()
 	w.Write(bb.Bytes())
 }
 
diff --git a/vendor/modules.txt b/vendor/modules.txt
index 8cbb0e15e..54e1003c5 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -12,7 +12,7 @@ cloud.google.com/go/storage
 github.com/BurntSushi/toml
 # github.com/VictoriaMetrics/fastcache v1.5.4
 github.com/VictoriaMetrics/fastcache
-# github.com/VictoriaMetrics/metrics v1.9.1
+# github.com/VictoriaMetrics/metrics v1.9.2
 github.com/VictoriaMetrics/metrics
 # github.com/aws/aws-sdk-go v1.25.43
 github.com/aws/aws-sdk-go/aws