ets vs. mnesia ram_copies

Sean Hinde <>
Tue Mar 11 20:17:29 CET 2003


> Does anyone have any tests they've put together comparing the
> performance of mnesia ram_copies (ram only tables, non replicated)
> and ets?  I'm trying to get an idea of the loss I'll have in
> performance by moving from ets to mnesia.
> 
> I realize it'll be slower.  And my case isn't necessarily what
> others tested, blah, blah, blah.  I just thought I'd seen a
> message about it a while ago, but couldn't find it in the
> archives.

I did some a long time ago, with old versions of erts and mnesia, and it was
indeed slower. I do seem to recall noticing that the number of hops from
mnesia:dirty_read to ets:lookup was reduced since then to almost nothing for
a local node, so I guess nowadays there is not much difference.

My test was a 10 liner which just inserted and read 100,000 rows or so - not
hard to recreate and not very sophisticated.

Sean



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