From 5595cad5ed538e696896cb9a54328453adcf2671 Mon Sep 17 00:00:00 2001
From: Chris Jansen <janstenpickle@users.noreply.github.com>
Date: Wed, 6 Sep 2023 17:04:46 +0100
Subject: [PATCH] Do not return previous exemplar in sampler

This avoids prom4cats unecessarily updating the exemplar ref when the
exemplar is not sampled. If this returns `None` then the ref won't be
updated and the previous will remain intact
---
 .../prometheus4cats/trace4cats/Trace4CatsExemplarSampler.scala   | 1 -
 1 file changed, 1 deletion(-)

diff --git a/trace4cats/src/main/scala/prometheus4cats/trace4cats/Trace4CatsExemplarSampler.scala b/trace4cats/src/main/scala/prometheus4cats/trace4cats/Trace4CatsExemplarSampler.scala
index b998ade..daad175 100644
--- a/trace4cats/src/main/scala/prometheus4cats/trace4cats/Trace4CatsExemplarSampler.scala
+++ b/trace4cats/src/main/scala/prometheus4cats/trace4cats/Trace4CatsExemplarSampler.scala
@@ -132,7 +132,6 @@ object Trace4CatsExemplarSampler extends Trace4CatsExemplarSamplerInstances {
           .filter(
             _.timestamp.toEpochMilli - prev.timestamp.toEpochMilli > minRetentionIntervalMs
           )
-          .orElse(previous)
       case None => next
     }
   }