From f46fb6c74069702597f2c6ca25e89cabbb3e6af9 Mon Sep 17 00:00:00 2001
From: Aliaksandr Valialkin <valyala@gmail.com>
Date: Mon, 25 Nov 2019 14:23:35 +0200
Subject: [PATCH] app/vmselect/promql: re-use metrics.Histogram when
 calculating histogram function for each point on the graph

This should reduce the amounts memory allocations
---
 app/vmselect/promql/aggr.go | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/app/vmselect/promql/aggr.go b/app/vmselect/promql/aggr.go
index 828fec4eb5..be856b7ebe 100644
--- a/app/vmselect/promql/aggr.go
+++ b/app/vmselect/promql/aggr.go
@@ -187,9 +187,10 @@ func aggrFuncGeomean(tss []*timeseries) []*timeseries {
 }
 
 func aggrFuncHistogram(tss []*timeseries) []*timeseries {
+	var h metrics.Histogram
 	m := make(map[string]*timeseries)
 	for i := range tss[0].Values {
-		var h metrics.Histogram
+		h.Reset()
 		for _, ts := range tss {
 			v := ts.Values[i]
 			h.Update(v)