[erlang-questions] "Erlang plus BDB: Disrupting the Conventional Web Wisdom"

Claes Wikstrom <>
Thu Oct 11 23:25:28 CEST 2007

Damien Morton wrote:
> Is there any reason why Mnesia couldnt use BDB instead of dets?

It could, and that would indeed remedy one of the weak points of
mnesia as of today, i.e. dets.
Dets is a fine module, but it is certainly beginning to show
its age. When it was written, 12 years ago, the 4G space limitation
seemed as a minor issue.

We need to do a dets rewrite which addresses the two issues
of size and repair speed. Once those two issues are fixed, I think
mnesia stands up just fine to the rest of the dbs out there. Until then
Mnesia only rock if we're sure that the amount of data in our largest
table is limited to a few Gig.

BDB is certainly a fine DB, but don't forget it's really expensive
unless you're whipping up a db backend for your local high school
or some such.


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