From 96218a10788b020c1ac762c3a5bc6c08ecfad16e Mon Sep 17 00:00:00 2001
From: Tatsuhiro Tsujikawa <tatsuhiro.t@gmail.com>
Date: Thu, 16 Jun 2016 23:04:06 +0900
Subject: [PATCH] nghttpx: Fast backend replacement on multi thread environment

---
 src/shrpx_worker.cc | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/shrpx_worker.cc b/src/shrpx_worker.cc
index d5c6967f..88a1084d 100644
--- a/src/shrpx_worker.cc
+++ b/src/shrpx_worker.cc
@@ -162,11 +162,15 @@ void Worker::replace_downstream_config(
 
   downstreamconf_ = downstreamconf;
 
-  downstream_addr_groups_ = std::vector<std::shared_ptr<DownstreamAddrGroup>>(
-      downstreamconf->addr_groups.size());
+  // Making a copy is much faster with multiple thread on
+  // backendconfig API call.
+  auto groups = downstreamconf->addr_groups;
 
-  for (size_t i = 0; i < downstreamconf->addr_groups.size(); ++i) {
-    auto &src = downstreamconf->addr_groups[i];
+  downstream_addr_groups_ =
+      std::vector<std::shared_ptr<DownstreamAddrGroup>>(groups.size());
+
+  for (size_t i = 0; i < groups.size(); ++i) {
+    auto &src = groups[i];
     auto &dst = downstream_addr_groups_[i];
 
     dst = std::make_shared<DownstreamAddrGroup>();