mnesia, large datasets and key range lookups

Jouni Rynö <>
Tue Jul 13 12:35:34 CEST 2004


On Tue, 2004-07-13 at 11:59 +0200,  wrote:
> > [..]
> > It's not an ordered set, but a bag.
> 
> Yes, but if you put all the parameters for one timestamp into one record, and
> have a key which is only the time, then it COULD be an ordered set, with all the
> advantages that brings. That's effectively what our archiving systems do here,
> for exectly the performance reason you're investigating (of course, and
> unfortunately, our systems are not implemented in Erlang -- maybe one day I can
> change that!).
> 
Maybe the day, when this statement from the mnesia manual disappears:
"Note: currently 'ordered_set' is not supported for 'disc_only_copies'
tables." 
I don't think I have enough memory in my machines to keep the data in
the RAM :(.

The fragmented tables feature in the mnesia seems at the moment at least
a fun way to continue ... 

Jouni
-- 

  Jouni Rynö                            mailto://Jouni.Ryno@fmi.fi/
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