[erlang-questions] On using Mnesia to pass data

Ludovic Coquelle <>
Wed Mar 7 06:39:42 CET 2007


(re-post some exchange I forgot to copy to the list)

Thanks, most of my current knowledge is based on a lot of "2 cents" ... so I
always enjoy to got some more! :)

I understand that slave can write in the remote table of master.
But my point was that there will be some overhead due to mnesia to share all
the schema/actions between master and slaves. I don't care about schema/data
exchange between master and one slave, but I wonder if mnesia has to make
connection between all slaves to know who is writing what, when, where ...

On 3/7/07, t ty <> wrote:
>
> You do not have to replicate the data. Is possible to have the slave
> see the data as a remote table. In this case the data from one slave
> isn't propagated to the other slaves.
>
> Overall I would consider mnesia overkill for your needs. But thats
> just my 2 cents.
>
> Regards
>
> t
>
> On 3/6/07, Ludovic Coquelle <> wrote:
> > Hi everyone,
> > I would like some advice on "using mnesia or not".
> >
> > The problem I try to solve: A master node run some processes on slave
> nodes,
> > and gather results of all those processes (master needs to know/admin
> which
> > process is start on which slave node; the context is a small
> load-testing
> > tool I am writing mostly to learn Erlang/OTP).
> >
> > Current implementation is fairly simple/direct: Master start the
> processes
> > on slaves, and wait that the slaves send back results.
> >
> > Looks like using mnesia could give me another implementation to solve
> the
> > problem: slave write data to mnesia, master read mnesia.
> > Is it a "good idea" to use mnesia only for data transfer? (don't care
> for
> > now that master will have to store data in some db, it's another issue)
> >
> > Advantage I see to mnesia is that I don't have to manage all cases where
> > slave failed before the end, send half the data only, send all data once
> or
> > piece by piece...
> > Drawback is maybe efficiency: master and all the slaves will share all
> the
> > data, where I only need a data transfer from slave->master ... looks
> like
> > mnesia will do more than what I need: am I in such a case where "when
> you
> > have a hammer everything looks like a nail"?
> >
> > Any thought?
> >
> > _______________________________________________
> > erlang-questions mailing list
> > 
> > http://www.erlang.org/mailman/listinfo/erlang-questions
> >
> >
>
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