From 77ba5c5fbdbf0623b630e604e862afc07115fc00 Mon Sep 17 00:00:00 2001
From: Bryan Boreham <bjboreham@gmail.com>
Date: Thu, 13 Nov 2025 18:16:29 +0000
Subject: [PATCH] [PERF] Scraping: skip an unnecessary step when there are
 relabel rules

Before it would do Builder->Labels->Builder, now we skip the conversions.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
---
 scrape/scrape.go | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/scrape/scrape.go b/scrape/scrape.go
index bbb93c8801..b8f0efce3c 100644
--- a/scrape/scrape.go
+++ b/scrape/scrape.go
@@ -716,13 +716,9 @@ func mutateSampleLabels(lset labels.Labels, target *Target, honor bool, rc []*re
 		}
 	}
 
-	res := lb.Labels()
+	relabel.ProcessBuilder(lb, rc...)
 
-	if len(rc) > 0 {
-		res, _ = relabel.Process(res, rc...)
-	}
-
-	return res
+	return lb.Labels()
 }
 
 func resolveConflictingExposedLabels(lb *labels.Builder, conflictingExposedLabels []labels.Label) {