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authorSimon MacMullen <simon@rabbitmq.com>2014-03-11 14:07:40 +0000
committerSimon MacMullen <simon@rabbitmq.com>2014-03-11 14:07:40 +0000
commit8a6a5594335adec0ddb13ad382269d0cfb694223 (patch)
tree4a48164b04f8ce69fba9b25a8e374f07797e8446
parentf3576738879eee8e4fba089a5f754246724b5adf (diff)
downloadrabbitmq-server-8a6a5594335adec0ddb13ad382269d0cfb694223.tar.gz
Avoid connecting to nodes that are down.
-rw-r--r--src/pmon.erl22
1 files changed, 20 insertions, 2 deletions
diff --git a/src/pmon.erl b/src/pmon.erl
index 86308167..e76ebd2f 100644
--- a/src/pmon.erl
+++ b/src/pmon.erl
@@ -54,8 +54,13 @@ new(Module) -> #state{dict = dict:new(),
monitor(Item, S = #state{dict = M, module = Module}) ->
case dict:is_key(Item, M) of
true -> S;
- false -> S#state{dict = dict:store(
- Item, Module:monitor(process, Item), M)}
+ false -> case node_alive_shortcut(Item) of
+ true -> Ref = Module:monitor(process, Item),
+ S#state{dict = dict:store(Item, Ref, M)};
+ false -> self() ! {'DOWN', fake_ref, process, Item,
+ nodedown},
+ S
+ end
end.
monitor_all([], S) -> S; %% optimisation
@@ -76,3 +81,16 @@ erase(Item, S = #state{dict = M}) -> S#state{dict = dict:erase(Item, M)}.
monitored(#state{dict = M}) -> dict:fetch_keys(M).
is_empty(#state{dict = M}) -> dict:size(M) == 0.
+
+%%----------------------------------------------------------------------------
+
+%% We check here to see if the node is alive in order to avoid trying
+%% to connect to it if it isn't - this can cause substantial
+%% slowdowns. We can't perform this shortcut if passed {Name, Node}
+%% since we would need to convert that into a pid for the fake 'DOWN'
+%% message, so we always return true here - but that's OK, it's just
+%% an optimisation.
+node_alive_shortcut(P) when is_pid(P) ->
+ lists:member(node(P), [node() | nodes()]);
+node_alive_shortcut({_Name, _Node}) ->
+ true.