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Merged
dumbbell merged 2 commits into from
Apr 8, 2026
Merged

rabbit_db: Eliminate the delete_queue Khepri transaction #14902

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6eeb339
rabbit_khepri: Fix typo, s/detele/delete/
dumbbell Apr 1, 2026
de43879
rabbit_db: Eliminate the `delete_queue` Khepri transaction
dumbbell Nov 5, 2025
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12 changes: 12 additions & 0 deletions deps/rabbit/src/rabbit_core_ff.erl
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Original file line number Diff line number Diff line change
Expand Up @@ -232,3 +232,15 @@
stability => stable,
depends_on => ['rabbitmq_4.3.0']
}}).

-rabbit_feature_flag(
{tie_binding_to_dest_with_keep_while_cond,
#{desc =>
"Use keep_while condition to tie a binding record lifetime to its "
"destination record in Khepri",
stability => stable,
depends_on => ['rabbitmq_4.3.0'],
callbacks => #{enable =>
{rabbit_db_queue,
tie_binding_to_dest_with_keep_while_cond_enable}}
}}).
143 changes: 136 additions & 7 deletions deps/rabbit/src/rabbit_db_binding.erl
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Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,9 @@
delete_for_destination_in_khepri/2,
delete_all_for_exchange_in_khepri/3,
has_for_source_in_khepri/1,
match_source_and_destination_in_khepri_tx/2
match_source_and_destination_in_khepri_tx/2,
khepri_ret_to_deletions/2,
put_options/1
]).

-export([
Expand Down Expand Up @@ -123,6 +125,12 @@ create(#binding{source = SrcName,
case ChecksFun(Src, Dst) of
ok ->
RoutePath = khepri_route_path(Binding),
FeatureFlag = rabbit_feature_flags:is_enabled(
tie_binding_to_dest_with_keep_while_cond),
PutOptions = case FeatureFlag of
true -> put_options(DstName);
false -> #{}
end,
MaybeSerial = rabbit_exchange:serialise_events(Src),
Serial = rabbit_khepri:transaction(
fun() ->
Expand All @@ -132,11 +140,17 @@ create(#binding{source = SrcName,
true ->
already_exists;
false ->
ok = khepri_tx:put(RoutePath, sets:add_element(Binding, Set)),
ok = khepri_tx:put(
RoutePath,
sets:add_element(Binding, Set),
PutOptions),
serial_in_khepri(MaybeSerial, Src)
end;
_ ->
ok = khepri_tx:put(RoutePath, sets:add_element(Binding, sets:new([{version, 2}]))),
ok = khepri_tx:put(
RoutePath,
sets:add_element(Binding, sets:new([{version, 2}])),
PutOptions),
serial_in_khepri(MaybeSerial, Src)
end
end, rw),
Expand Down Expand Up @@ -166,6 +180,30 @@ lookup_resource(#resource{kind = exchange} = Name) ->
_ -> []
end.

put_options(#resource{virtual_host = VHost, name = DstName, kind = Kind}) ->
put_options(VHost, DstName, Kind);
put_options(BindingPath) when is_list(BindingPath) ->
{
VHost,
_SrcName,
Kind,
DstName,
_RoutingKey
} = rabbit_db_binding:khepri_route_path_to_args(BindingPath),
put_options(VHost, DstName, Kind).

put_options(VHost, DstName, Kind) ->
DstPath = case Kind of
queue ->
rabbit_db_queue:khepri_queue_path(
VHost, DstName);
exchange ->
rabbit_db_exchange:khepri_exchange_path(
VHost, DstName)
end,
KeepWhile = #{DstPath => #if_node_exists{}},
#{keep_while => KeepWhile}.

serial_in_khepri(false, _) ->
none;
serial_in_khepri(true, X) ->
Expand All @@ -190,8 +228,18 @@ serial_in_khepri(true, X) ->
%%
%% @private

delete(#binding{source = SrcName,
destination = DstName} = Binding, ChecksFun) ->
delete(Binding, ChecksFun) ->
FeatureFlag = rabbit_feature_flags:is_enabled(
tie_binding_to_dest_with_keep_while_cond),
case FeatureFlag of
true ->
delete_v2(Binding, ChecksFun);
false ->
delete_v1(Binding, ChecksFun)
end.

delete_v1(#binding{source = SrcName,
destination = DstName} = Binding, ChecksFun) ->
Path = khepri_route_path(Binding),
case rabbit_khepri:transaction(
fun () ->
Expand All @@ -204,7 +252,7 @@ delete(#binding{source = SrcName,
true ->
case ChecksFun(Src, Dst) of
ok ->
ok = delete_in_khepri(Binding),
ok = delete_in_khepri_tx_v1(Binding),
maybe_auto_delete_exchange_in_khepri(Binding#binding.source, [Binding], rabbit_binding:new_deletions(), false);
{error, _} = Err ->
Err
Expand All @@ -224,6 +272,40 @@ delete(#binding{source = SrcName,
{ok, Deletions}
end.

delete_v2(#binding{source = SrcName,
destination = DstName} = Binding, ChecksFun) ->
Path = khepri_route_path(Binding),
case rabbit_khepri:transaction(
fun () ->
case {lookup_resource_in_khepri_tx(SrcName),
lookup_resource_in_khepri_tx(DstName)} of
{[Src], [Dst]} ->
case exists_in_khepri(Path, Binding) of
false ->
ok;
true ->
case ChecksFun(Src, Dst) of
ok ->
delete_in_khepri_tx_v2(Binding);
{error, _} = Err ->
Err
end
end;
_Errs ->
%% No absent queues, always present on disk
ok
end
end) of
ok ->
ok;
{error, _} = Err ->
Err;
{ok, Deleted} ->
Deletions = khepri_ret_to_deletions(Deleted, false),
ok = rabbit_binding:process_deletions(Deletions),
{ok, Deletions}
end.

exists_in_khepri(Path, Binding) ->
case khepri_tx:get(Path) of
{ok, Set} ->
Expand All @@ -232,7 +314,7 @@ exists_in_khepri(Path, Binding) ->
false
end.

delete_in_khepri(Binding) ->
delete_in_khepri_tx_v1(Binding) ->
Path = khepri_route_path(Binding),
case khepri_tx:get(Path) of
{ok, Set0} ->
Expand All @@ -247,6 +329,21 @@ delete_in_khepri(Binding) ->
ok
end.

delete_in_khepri_tx_v2(Binding) ->
Path = khepri_route_path(Binding),
case khepri_tx:get(Path) of
{ok, Set0} ->
Set = sets:del_element(Binding, Set0),
case sets:is_empty(Set) of
true ->
khepri_tx_adv:delete(Path);
false ->
ok = khepri_tx:put(Path, Set)
end;
_ ->
ok
end.

maybe_auto_delete_exchange_in_khepri(XName, Bindings, Deletions, OnlyDurable) ->
case rabbit_db_exchange:maybe_auto_delete_in_khepri(XName, OnlyDurable) of
{not_deleted, undefined} ->
Expand Down Expand Up @@ -562,6 +659,38 @@ delete_for_destination_in_khepri(#resource{virtual_host = VHost, kind = Kind, na
rabbit_binding:group_bindings_fold(fun maybe_auto_delete_exchange_in_khepri/4,
lists:keysort(#binding.source, Bindings), OnlyDurable).

khepri_ret_to_deletions(Deleted, OnlyDurable) ->
Bindings0 = maps:fold(
fun(Path, Props, Acc) ->
case {Path, Props} of
{?RABBITMQ_KHEPRI_ROUTE_PATH(
_VHost, _SrcName, _Kind, _Name, _RoutingKey),
#{data := Set}} ->
sets:to_list(Set) ++ Acc;
{_, _} ->
Acc
end
end, [], Deleted),
Bindings1 = lists:keysort(#binding.source, Bindings0),
rabbit_binding:group_bindings_fold(
fun(XName, Bindings, Deletions, _OnlyDurable) ->
ExchangePath = rabbit_db_exchange:khepri_exchange_path(XName),
case Deleted of
#{ExchangePath := #{data := X}} ->
rabbit_binding:add_deletion(
XName, X, deleted, Bindings, Deletions);
_ ->
case rabbit_db_exchange:get(XName) of
{ok, X} ->
rabbit_binding:add_deletion(
XName, X, not_deleted, Bindings, Deletions);
_ ->
Deletions
end
end
end,
Bindings1, OnlyDurable).

%% -------------------------------------------------------------------
%% has_for_source_in_khepri().
%% -------------------------------------------------------------------
Expand Down
28 changes: 26 additions & 2 deletions deps/rabbit/src/rabbit_db_exchange.erl
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Original file line number Diff line number Diff line change
Expand Up @@ -41,7 +41,8 @@
get_in_khepri_tx/1,
update_in_khepri_tx/2,
clear_exchanges_in_khepri/0,
clear_exchange_serials_in_khepri/0
clear_exchange_serials_in_khepri/0,
put_options/1
]).

%% For testing
Expand Down Expand Up @@ -284,7 +285,13 @@ create_or_get(#exchange{name = XName} = X) ->
Path0, [#if_any{conditions =
[#if_node_exists{exists = false},
#if_has_payload{has_payload = false}]}]),
case rabbit_khepri:put(Path1, X) of
FeatureFlag = rabbit_feature_flags:is_enabled(
tie_binding_to_dest_with_keep_while_cond),
PutOptions = case FeatureFlag of
true -> put_options(X);
false -> #{}
end,
case rabbit_khepri:put(Path1, X, PutOptions) of
ok ->
{new, X};
{error, {khepri, mismatching_node, #{node_props := #{data := ExistingX}}}} ->
Expand All @@ -293,6 +300,23 @@ create_or_get(#exchange{name = XName} = X) ->
Err
end.

put_options(Exchange) ->
case Exchange of
#exchange{name = #resource{virtual_host = VHost,
name = Name},
auto_delete = true} ->
Path = rabbit_db_binding:khepri_route_path(
VHost,
Name,
_Kind = ?KHEPRI_WILDCARD_STAR,
_DstName = ?KHEPRI_WILDCARD_STAR,
_RoutingKey = ?KHEPRI_WILDCARD_STAR),
KeepWhile = #{Path => #if_has_data{}},
#{keep_while => KeepWhile};
_ ->
#{}
end.

%% -------------------------------------------------------------------
%% set().
%% -------------------------------------------------------------------
Expand Down
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