From 614d9f48cc38ec5d68d8440c6d929db40ac75440 Mon Sep 17 00:00:00 2001
From: Martin Sumner <martin.sumner@adaptip.co.uk>
Date: Mon, 15 Jun 2020 21:06:06 +0100
Subject: [PATCH 1/2] Disable soft-limit check

Modified version of https://github.com/basho/riak_kv/pull/1757 to allow cuttlefisk config setting of option via riak.conf
---
 priv/riak_kv.schema     | 11 +++++++++++
 src/riak_kv_put_fsm.erl |  5 ++++-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/priv/riak_kv.schema b/priv/riak_kv.schema
index 75fade4265..52b0ae2a28 100644
--- a/priv/riak_kv.schema
+++ b/priv/riak_kv.schema
@@ -439,6 +439,17 @@
   hidden
 ]}.
 
+%% @doc Enable or disable mbox_check on PUTs
+%% By default mbox_checks are performed so that vnodes with long queues
+%% will not be used as put coordinators.  To return to the pre-2.9 behaviour
+%% of not checking, this can be disabled.  The mbox_check may add additional
+%% latency to PUTs in some environments.
+{mapping, "mbox_check_enabled", "riak_kv.mbox_check_enabled", [
+    {default, on},
+    {datatype, flag},
+    hidden
+]}
+
 %% @doc Controls which binary representation of a riak value is stored
 %% on disk.
 %% * 0: Original erlang:term_to_binary format. Higher space overhead.
diff --git a/src/riak_kv_put_fsm.erl b/src/riak_kv_put_fsm.erl
index 8764ab1466..8e5e9c6b2f 100644
--- a/src/riak_kv_put_fsm.erl
+++ b/src/riak_kv_put_fsm.erl
@@ -1269,7 +1269,10 @@ get_soft_limit_option(Options) ->
     %% both the system (post forward) and the client (via options) can
     %% turn off soft-limit checking. However, by default, we should
     %% use them (if supported)
-    SoftLimitedWanted = get_option(mbox_check, Options, SoftLimitSupported),
+    SoftLimitedWanted =
+        app_helper:get_env(riak_kv, mbox_check_enabled, true) andalso
+        SoftLimitSupported andalso
+        get_option(mbox_check, Options, SoftLimitSupported),
     SoftLimitedWanted.
 
 

From b825588c929781f215cfdf0d5c6f0afcb4e5a8be Mon Sep 17 00:00:00 2001
From: Martin Sumner <martin.sumner@adaptip.co.uk>
Date: Mon, 15 Jun 2020 21:23:36 +0100
Subject: [PATCH 2/2] Missing .

---
 priv/riak_kv.schema | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/priv/riak_kv.schema b/priv/riak_kv.schema
index 52b0ae2a28..58cf934d12 100644
--- a/priv/riak_kv.schema
+++ b/priv/riak_kv.schema
@@ -448,7 +448,7 @@
     {default, on},
     {datatype, flag},
     hidden
-]}
+]}.
 
 %% @doc Controls which binary representation of a riak value is stored
 %% on disk.