Revert "Default to classic queues v2"

This reverts commit a404b49.

Author: Loïc Hoguin

deps/rabbit/BUILD.bazel

@@ -85,8 +85,6 @@ _APP_ENV = """[
 	                         ]},
 	    {halt_on_upgrade_failure, true},
 	    {ssl_apps, [asn1, crypto, public_key, ssl]},
-	    %% classic queue storage implementation version
-	    {classic_queue_default_version, 2},
 	    %% see rabbitmq-server#114
 	    {mirroring_flow_control, true},
 	    {mirroring_sync_batch_size, 4096},

deps/rabbit/Makefile

@@ -65,8 +65,6 @@ define PROJECT_ENV
 	                         ]},
 	    {halt_on_upgrade_failure, true},
 	    {ssl_apps, [asn1, crypto, public_key, ssl]},
-	    %% classic queue storage implementation version
-	    {classic_queue_default_version, 2},
 	    %% see rabbitmq-server#114
 	    {mirroring_flow_control, true},
 	    {mirroring_sync_batch_size, 4096},

deps/rabbit/priv/schema/rabbit.schema

@@ -2485,7 +2485,7 @@ end}.
 
 {translation, "rabbit.classic_queue_default_version",
     fun(Conf) ->
-        case cuttlefish:conf_get("classic_queue.default_version", Conf, 2) of
+        case cuttlefish:conf_get("classic_queue.default_version", Conf, 1) of
             1 -> 1;
             2 -> 2;
             _ -> cuttlefish:unset()

deps/rabbit/src/rabbit_amqqueue_process.erl

@@ -470,12 +470,12 @@ init_queue_mode(Mode, State = #q {backing_queue = BQ,
 
 init_queue_version(Version0, State = #q {backing_queue = BQ,
                                          backing_queue_state = BQS}) ->
-    %% When the version is undefined we use the default version 2.
+    %% When the version is undefined we use the default version 1.
     %% We want to BQ:set_queue_version in all cases because a v2
     %% policy might have been deleted, for example, and we want
     %% the queue to go back to v1.
     Version = case Version0 of
-        undefined -> rabbit_misc:get_env(rabbit, classic_queue_default_version, 2);
+        undefined -> rabbit_misc:get_env(rabbit, classic_queue_default_version, 1);
         _ -> Version0
     end,
     BQS1 = BQ:set_queue_version(Version, BQS),

deps/rabbit/src/rabbit_variable_queue.erl

@@ -489,11 +489,10 @@ process_recovery_terms(Terms) ->
         PRef      -> {PRef, Terms}
     end.
 
-%% If queue-version is undefined, we assume v2 starting with RabbitMQ 3.13.0.
 queue_version(Q) ->
     Resolve = fun(_, ArgVal) -> ArgVal end,
     case rabbit_queue_type_util:args_policy_lookup(<<"queue-version">>, Resolve, Q) of
-        undefined -> rabbit_misc:get_env(rabbit, classic_queue_default_version, 2);
+        undefined -> rabbit_misc:get_env(rabbit, classic_queue_default_version, 1);
         Vsn when is_integer(Vsn) -> Vsn;
         Vsn -> binary_to_integer(Vsn)
     end.

release-notes/3.13.0.md

@@ -240,21 +240,6 @@ Release notes are kept under [rabbitmq-server/release-notes](https://github.com/
 
    GitHub issue: [#8218](https://github.com/rabbitmq/rabbitmq-server/pull/8218)
 
- * Reduced memory footprint, improved memory use predictability and throughput of classic queues (version 2, or CQv2).
-   This particularly benefits classic queues with longer backlogs.
-
-   Classic queue v2 (CQv2) storage implementation **is now the default**. It is possible to switch
-   the default back to CQv1 using `rabbitmq.conf`:
-
-   ``` ini
-   # uses CQv1 by default
-   classic_queue.default_version = 1
-   ```
-
-   Individual queues can be declared by passing `x-queue-version` argument and/or through a `queue-version` policy.
-
-   GitHub issue: [#8308](https://github.com/rabbitmq/rabbitmq-server/pull/8308)
-
  * Revisited peer discovery implementation that further reduces the probability of two or more
    sets of nodes [forming separate clusters](https://www.rabbitmq.com/cluster-formation.html#initial-formation-race-condition) when **all** cluster nodes are created at the same time and boot in parallel.