From bb37769d0474368c400ed520baad707e3709db72 Mon Sep 17 00:00:00 2001
From: zhengchenyu <zhengchenyu16@163.com>
Date: Wed, 18 Oct 2023 17:18:42 +0800
Subject: [PATCH] add comment

---
 .../common/shuffle/orderedgrouped/RssInMemoryMerger.java       | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/client-tez/src/main/java/org/apache/tez/runtime/library/common/shuffle/orderedgrouped/RssInMemoryMerger.java b/client-tez/src/main/java/org/apache/tez/runtime/library/common/shuffle/orderedgrouped/RssInMemoryMerger.java
index c9da9a4663..11c003e897 100644
--- a/client-tez/src/main/java/org/apache/tez/runtime/library/common/shuffle/orderedgrouped/RssInMemoryMerger.java
+++ b/client-tez/src/main/java/org/apache/tez/runtime/library/common/shuffle/orderedgrouped/RssInMemoryMerger.java
@@ -176,6 +176,9 @@ public void merge(List<MapOutput> inputs) throws IOException, InterruptedExcepti
       } else {
         runCombineProcessor(rIter, writer);
       }
+      // The compressed length of writer is calculated when called Writer::close, we must
+      // update the counter after Writer::close. Counter should be updated in normal
+      // execution flow, so do not update counter in finally block.
       writer.close();
       additionalBytesWritten.increment(writer.getCompressedLength());
       writer = null;