From c5e0f527bcd6033e571dfced32d97594d1798ba5 Mon Sep 17 00:00:00 2001
From: Aliaksandr Valialkin <valyala@victoriametrics.com>
Date: Mon, 9 Jan 2023 21:53:07 -0800
Subject: [PATCH] app/vmselect/netstorage: cache canonical MetricName for time
 series returned from the storage

This reduces memory allocations for repeated queries, which return (almost) the same set of time series.
---
 app/vmselect/netstorage/netstorage.go | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/app/vmselect/netstorage/netstorage.go b/app/vmselect/netstorage/netstorage.go
index e4026df7b..408766e90 100644
--- a/app/vmselect/netstorage/netstorage.go
+++ b/app/vmselect/netstorage/netstorage.go
@@ -1090,8 +1090,8 @@ func ProcessSearchQuery(qt *querytracer.Tracer, sq *storage.SearchQuery, deadlin
 			putStorageSearch(sr)
 			return nil, fmt.Errorf("cannot write %d bytes to temporary file: %w", len(buf), err)
 		}
-		metricName := sr.MetricBlockRef.MetricName
-		brs := m[string(metricName)]
+		metricName := bytesutil.InternBytes(sr.MetricBlockRef.MetricName)
+		brs := m[metricName]
 		if brs == nil {
 			brs = &blockRefs{}
 		}
@@ -1100,10 +1100,8 @@ func ProcessSearchQuery(qt *querytracer.Tracer, sq *storage.SearchQuery, deadlin
 			addr:    addr,
 		})
 		if len(brs.brs) == 1 {
-			// An optimization for big number of time series with long metricName values:
-			// use only a single copy of metricName for both orderedMetricNames and m.
-			orderedMetricNames = append(orderedMetricNames, string(metricName))
-			m[orderedMetricNames[len(orderedMetricNames)-1]] = brs
+			orderedMetricNames = append(orderedMetricNames, metricName)
+			m[metricName] = brs
 		}
 	}
 	if err := sr.Error(); err != nil {