[erlang-questions] gen_server:multi_call/3 causing unexpected invocation of handle_info/2
Thu Dec 27 07:21:50 CET 2007
I have written an Erlang application that uses gen_server:multi_call/
3, (so the timeout is infinity). I have also written a little test
program that does the following:
- Starts three VMs on one machine.
- Occasionally kills one of the VMs (using kill -9) and then restarts
it. (This is intended to simulate a node crashing in a cluster with
one VM per node.)
- Checks to see that the application is responding to the failure as
I will typically do 1000 VM bounces in a single test run. I
occasionally see errors due to unexpected calls to
gen_server:handle_info/2, which appear to be connected to the
multi_call. The cases I've examined have these characteristics:
- The multi_call invocation returns one of the nodes in the BadNodes
part of the multi_call result.
- I retry the request to the nodes listed in BadNodes and the request
- The ORIGINAL invocation to the node actually did reach the node and
eventually execute. The response eventually reaches the node that
issued the original request, and is routed to handle_info.
I've read the documentation for multi_call, and this behavior does
not appear to be documented. This paragraph from the documentation
addresses late delivery:
To avoid that late answers (after the timeout) pollutes the
message queue, a middleman process is used to do the actual
calls. Late answers will then be discarded when they arrive to a
but 1) my timeout is infinity, and 2) the calling process has not
The behavior I'm seeing does not appear to be documented -- is it
I'm running on a MacBook Pro, and erl -version says: Erlang
(ASYNC_THREADS) (BEAM) emulator version 5.5.1.
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