From e7c117ef190d77bb09de0ca31835c79646b7b4f5 Mon Sep 17 00:00:00 2001
From: ieQu1 <99872536+ieQu1@users.noreply.github.com>
Date: Wed, 20 Jul 2022 15:53:51 +0200
Subject: [PATCH] fix(shared_session): Don't redispatch inflight messages on
 takeover

---
 CHANGES-4.3.md       |  1 +
 src/emqx.appup.src   | 12 ++++++++----
 src/emqx_session.erl |  3 ++-
 3 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/CHANGES-4.3.md b/CHANGES-4.3.md
index ecca0dc8b..299900da9 100644
--- a/CHANGES-4.3.md
+++ b/CHANGES-4.3.md
@@ -22,6 +22,7 @@ File format:
 ### Enhancements
 - HTTP API(GET /rules/) support for pagination and fuzzy filtering. [#8450]
 - Add check_conf cli to check config format. [#8486]
+- Optimize performance of shared subscription
 
 ## v4.3.16
 
diff --git a/src/emqx.appup.src b/src/emqx.appup.src
index bad08dba2..780bb3c82 100644
--- a/src/emqx.appup.src
+++ b/src/emqx.appup.src
@@ -2,12 +2,14 @@
 %% Unless you know what you are doing, DO NOT edit manually!!
 {VSN,
   [{"4.3.17",
-    [{load_module,emqx_shared_sub,brutal_purge,soft_purge,[]},
+    [{load_module,emqx_session,brutal_purge,soft_purge,[]},
+     {load_module,emqx_shared_sub,brutal_purge,soft_purge,[]},
      {update,emqx_broker_sup,supervisor},
      {load_module,emqx_app,brutal_purge,soft_purge,[]},
      {load_module,emqx_access_control,brutal_purge,soft_purge,[]}]},
    {"4.3.16",
-    [{load_module,emqx_shared_sub,brutal_purge,soft_purge,[]},
+    [{load_module,emqx_session,brutal_purge,soft_purge,[]},
+     {load_module,emqx_shared_sub,brutal_purge,soft_purge,[]},
      {update,emqx_broker_sup,supervisor},
      {load_module,emqx_access_control,brutal_purge,soft_purge,[]},
      {load_module,emqx_plugins,brutal_purge,soft_purge,[]},
@@ -675,12 +677,14 @@
      {load_module,emqx_limiter,brutal_purge,soft_purge,[]}]},
    {<<".*">>,[]}],
   [{"4.3.17",
-    [{load_module,emqx_shared_sub,brutal_purge,soft_purge,[]},
+    [{load_module,emqx_session,brutal_purge,soft_purge,[]},
+     {load_module,emqx_shared_sub,brutal_purge,soft_purge,[]},
      {update,emqx_broker_sup,supervisor},
      {load_module,emqx_app,brutal_purge,soft_purge,[]},
      {load_module,emqx_access_control,brutal_purge,soft_purge,[]}]},
    {"4.3.16",
-    [{load_module,emqx_shared_sub,brutal_purge,soft_purge,[]},
+    [{load_module,emqx_session,brutal_purge,soft_purge,[]},
+     {load_module,emqx_shared_sub,brutal_purge,soft_purge,[]},
      {update,emqx_broker_sup,supervisor},
      {load_module,emqx_access_control,brutal_purge,soft_purge,[]},
      {load_module,emqx_plugins,brutal_purge,soft_purge,[]},
diff --git a/src/emqx_session.erl b/src/emqx_session.erl
index 20a61b4f6..94483bb87 100644
--- a/src/emqx_session.erl
+++ b/src/emqx_session.erl
@@ -627,7 +627,8 @@ replay(ClientInfo, Session = #session{inflight = Inflight}) ->
 -spec(terminate(emqx_types:clientinfo(), Reason :: term(), session()) -> ok).
 terminate(ClientInfo, Reason, Session) ->
     run_terminate_hooks(ClientInfo, Reason, Session),
-    redispatch_shared_messages(Session),
+    Reason =/= takeovered andalso
+        redispatch_shared_messages(Session),
     ok.
 
 run_terminate_hooks(ClientInfo, discarded, Session) ->