From e3c9f1544a1a18363fb51eac347264d19d7cd34a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Markus=20M=C3=A4kel=C3=A4?= <markus.makela@mariadb.com>
Date: Thu, 4 Mar 2021 11:12:04 +0200
Subject: [PATCH] Backport fix for MXS-3392 to 2.4

This solves problems with connectors that unconditionally send a
COM_STMT_PREPARE.
---
 .../modules/routing/readwritesplit/rwsplit_route_stmt.cc | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/server/modules/routing/readwritesplit/rwsplit_route_stmt.cc b/server/modules/routing/readwritesplit/rwsplit_route_stmt.cc
index fa42754a7..db15013b6 100644
--- a/server/modules/routing/readwritesplit/rwsplit_route_stmt.cc
+++ b/server/modules/routing/readwritesplit/rwsplit_route_stmt.cc
@@ -305,7 +305,14 @@ bool RWSplitSession::route_single_stmt(GWBUF* querybuf)
         else if (mxs_mysql_is_ps_command(command) && stmt_id == 0)
         {
             // Unknown prepared statement ID
-            succp = send_unknown_ps_error(extract_binary_ps_id(querybuf));
+            if (mxs_mysql_command_will_respond(command))
+            {
+                succp = send_unknown_ps_error(extract_binary_ps_id(querybuf));
+            }
+            else
+            {
+                succp = true;
+            }
         }
         else if (TARGET_IS_NAMED_SERVER(route_target) || TARGET_IS_RLAG_MAX(route_target))
         {