From 2b7798608d0676cc24245104b5ab24ef66dd48bf Mon Sep 17 00:00:00 2001
From: Serge Tupchii <serge.tupchii@protonmail.com>
Date: Fri, 4 Aug 2023 16:55:36 +0300
Subject: [PATCH] fix(emqx_router_helper): don't cleanup down node on a
 replicant

The cleanup on a replicant node is redundant, as Mria would delegate this delete op
to a core node (via RPC), and the core node is expected to receive the same
`nodedown` message and process it.
---
 apps/emqx/src/emqx_router_helper.erl | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/apps/emqx/src/emqx_router_helper.erl b/apps/emqx/src/emqx_router_helper.erl
index 78cf62d6c..8d96bf81d 100644
--- a/apps/emqx/src/emqx_router_helper.erl
+++ b/apps/emqx/src/emqx_router_helper.erl
@@ -146,13 +146,18 @@ handle_info({mnesia_table_event, Event}, State) ->
     ?SLOG(debug, #{msg => "unexpected_mnesia_table_event", event => Event}),
     {noreply, State};
 handle_info({nodedown, Node}, State = #{nodes := Nodes}) ->
-    global:trans(
-        {?LOCK, self()},
-        fun() ->
-            mria:transaction(?ROUTE_SHARD, fun ?MODULE:cleanup_routes/1, [Node])
-        end
-    ),
-    ok = mria:dirty_delete(?ROUTING_NODE, Node),
+    case mria_rlog:role() of
+        core ->
+            global:trans(
+                {?LOCK, self()},
+                fun() ->
+                    mria:transaction(?ROUTE_SHARD, fun ?MODULE:cleanup_routes/1, [Node])
+                end
+            ),
+            ok = mria:dirty_delete(?ROUTING_NODE, Node);
+        replicant ->
+            ok
+    end,
     ?tp(emqx_router_helper_cleanup_done, #{node => Node}),
     {noreply, State#{nodes := lists:delete(Node, Nodes)}, hibernate};
 handle_info({membership, {mnesia, down, Node}}, State) ->