From 4bf79d6d1b6e2cdcdab799c375b68b74f47aed56 Mon Sep 17 00:00:00 2001
From: Jack Berg <34418638+jack-berg@users.noreply.github.com>
Date: Fri, 6 Mar 2026 08:44:38 -0600
Subject: [PATCH] Clear id cache before flushing output to resolve memory leak
 under load

---
 .../exporter/internal/marshal/ProtoSerializer.java              | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exporters/common/src/main/java/io/opentelemetry/exporter/internal/marshal/ProtoSerializer.java b/exporters/common/src/main/java/io/opentelemetry/exporter/internal/marshal/ProtoSerializer.java
index 79bcd861ddd..8d815e19a6c 100644
--- a/exporters/common/src/main/java/io/opentelemetry/exporter/internal/marshal/ProtoSerializer.java
+++ b/exporters/common/src/main/java/io/opentelemetry/exporter/internal/marshal/ProtoSerializer.java
@@ -277,9 +277,9 @@ public void writeSerializedMessage(byte[] protoSerialized, String jsonSerialized
 
   @Override
   public void close() throws IOException {
+    idCache.clear();
     try {
       output.flush();
-      idCache.clear();
     } catch (IOException e) {
       // If close is called automatically as part of try-with-resources, it's possible that
       // output.flush() will throw the same exception. Re-throwing the same exception in a finally