# erlang/Mnesia adaptor for rails **URL:** \ **Category:** Rails\ **Created:** [September 9, 2007, 3:48am UTC](https://www.ruby-forum.com/t/erlang-mnesia-adaptor-for-rails/114172 "2007-09-09T03:48:18Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![snacktime](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/7feea3/32.png) [@snacktime](https://www.ruby-forum.com/u/snacktime)\ **Post date:** [September 9, 2007, 3:48am UTC](https://www.ruby-forum.com/t/erlang-mnesia-adaptor-for-rails/114172/1 "2007-09-09T03:48:18Z")
I’m working on a site that will most likely be huge and could easily be one of the largest ruby on rails sites yet. While we will be using databases to some extent on the backend, I know that’s only going to scale out so far, so I’ve been looking at some alternatives. Memcache is nice and I’m sure we will use it, but we are really looking for something more along the lines of a distributed rdbms. At the same time I’ve been playing around with erlang and mnesia for the first time. It seems to me that it should be possible to write an AR adaptor that communicates as a client to an erlang node via tcp, and have code on the node to translate sql into mnesia database calls. While translating sql would be a pain, supporting simple queries should be doable without too much effort. Anyone working on something like this, or have ideas on interfacing rails with erlang OTP systems? Chris ---
**Author:** ![snacktime](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/7feea3/32.png) [@snacktime](https://www.ruby-forum.com/u/snacktime)\ **Post date:** [September 10, 2007, 4:03am UTC](https://www.ruby-forum.com/t/erlang-mnesia-adaptor-for-rails/114172/2 "2007-09-10T04:03:43Z")
Read up on Erlang ports - that’s probably the mechanism I’d look at first to use in interfacing Rails with Erlang. The reason I’d look at it first is that it exists now, is fairly straightforward to implement and works. If for some reason it’s not going to work (and I can see that having to translate between SQL and Mnesia calls might be one reason not to use it), then I think you’re on the right track looking at something like a TCP socket connection. It might also be worth reading up on the limitations around massive Mnesia databases. Although I haven’t built anything particularly large with Mnesia, it seems as though some people are concerned with Mnesia’s ability to handle very large datasets and have been discussing this on the Erlang groups recently. Taking what I’ve read at strictly face value, I’d have concerns about it as well until I’d done some fairly rigorous investigation of my own. Regards Dave M. ---
**Author:** ![snacktime](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/7feea3/32.png) [@snacktime](https://www.ruby-forum.com/u/snacktime)\ **Post date:** [September 10, 2007, 5:03am UTC](https://www.ruby-forum.com/t/erlang-mnesia-adaptor-for-rails/114172/3 "2007-09-10T05:03:47Z")
On Sep 8, 2007, at 6:44 PM, snacktime wrote: > It seems to me that it should be possible to write an AR adaptor that > communicates as a client to an erlang node via tcp, and have code on > the node to translate sql into mnesia database calls. While > translating sql would be a pain, supporting simple queries should be > doable without too much effort. > > Anyone working on something like this, or have ideas on interfacing > rails with erlang OTP systems? > > Chris Chris- You might want to take a look at CouchDB. It’s built on erlang but exposes data as json objects over a REST interface with a map/reduce javascript query language. [http://couchdb.org/](http://couchdb.org/) Cheers- – Ezra Z. – Founder & Ruby Hacker – removed\_email\_address@domain.invalid – Engine Y., Serious Rails Hosting – (866) 518-YARD (9273)