From b564729d7537e693ab5a3c825bef14e48afc6f74 Mon Sep 17 00:00:00 2001
From: Aliaksandr Valialkin <valyala@victoriametrics.com>
Date: Wed, 14 Feb 2024 03:24:42 +0200
Subject: [PATCH] lib/promscrape: avoid copying labels when
 -promscrape.dropOriginalLabels command-line flag is set

This should save some CPU

This regression has been introduced in 487f6380d0b4f131fef6f5889e0b262d70f31b6e
when working on https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5389
---
 lib/promscrape/config.go | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/lib/promscrape/config.go b/lib/promscrape/config.go
index 323395c0a..3158d0b24 100644
--- a/lib/promscrape/config.go
+++ b/lib/promscrape/config.go
@@ -1077,7 +1077,10 @@ func (swc *scrapeWorkConfig) getScrapeWork(target string, extraLabels, metaLabel
 	defer promutils.PutLabels(labels)
 
 	mergeLabels(labels, swc, target, extraLabels, metaLabels)
-	originalLabels := labels.Clone()
+	var originalLabels *promutils.Labels
+	if !*dropOriginalLabels {
+		originalLabels = labels.Clone()
+	}
 	labels.Labels = swc.relabelConfigs.Apply(labels.Labels, 0)
 	// Remove labels starting from "__meta_" prefix according to https://www.robustperception.io/life-of-a-label/
 	labels.RemoveMetaLabels()
@@ -1212,7 +1215,7 @@ func (swc *scrapeWorkConfig) getScrapeWork(target string, extraLabels, metaLabel
 }
 
 func sortOriginalLabelsIfNeeded(originalLabels *promutils.Labels) *promutils.Labels {
-	if *dropOriginalLabels {
+	if originalLabels == nil {
 		return nil
 	}
 	originalLabels.Sort()