[erlang-questions] Mnesia activity callback system context

Paul Mineiro <>
Wed Jan 13 23:47:39 CET 2010


On Wed, 13 Jan 2010, Bernard Duggan wrote:

> Hi List,
>     Is it the case that mnesia activity callbacks are guaranteed to
> execute in the same process that is performing the transaction?  I can't
> find any mention of it in the docs.  I ask because if it's not, it
> doesn't seem like there's any way to get an arbitrary piece of
> information from the latter process to the one in which the callbacks
> execute, and that significantly limits their usefulness for a couple of
> things I'd like to do.  (I had written a long email explaining those
> things, but if the answer to this question is "yes" then I can save us
> all a lot of time :))
>     Even if the answer is "yes", it still seems like the only way would
> be to use the process dictionary - fine if that's the case, but it seems
> like there "should" be a neater way.

I don't have a strong aversion to the process dictionary, but
mnesia:activity/3,4 take a Fun (closure) and an Args (direct
information passing) both of which would facilitate passing information to
the callback.

So I suspect you're trying to do something unusual or interesting; maybe
the details would help?

-- p


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