From ae69f72b71b34504dbd74cd1d57658b7096a672e Mon Sep 17 00:00:00 2001
From: Masahiro Nakagawa <repeatedly@gmail.com>
Date: Wed, 24 May 2017 18:06:45 +0900
Subject: [PATCH] Don't call commit_write when can't get ack

---
 lib/fluent/plugin/out_forward.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/fluent/plugin/out_forward.rb b/lib/fluent/plugin/out_forward.rb
index b81f681c9d..712447b29f 100644
--- a/lib/fluent/plugin/out_forward.rb
+++ b/lib/fluent/plugin/out_forward.rb
@@ -495,7 +495,7 @@ def ack_reader
 
           readable_sockets.each do |sock|
             chunk_id = read_ack_from_sock(sock, unpacker)
-            commit_write(chunk_id)
+            commit_write(chunk_id) if chunk_id
           end
         rescue => e
           log.error "unexpected error while receiving ack", error: e