[ANN] ram, an in-memory distributed KV store

Led ledest@REDACTED
Wed Dec 22 15:43:12 CET 2021

> Let’s write a database! Well not really, but I think it’s a little sad that there doesn’t seem to be a simple in-memory distributed KV database in Erlang. Many times all I need is a consistent distributed ETS table.
> The two main ones I normally consider are:
> Riak which is great, it handles loads of data and is based on DHTs. This means that when there are cluster changes there is a need for redistribution of data and the process needs to be properly managed, with handoffs and so on. It is really great but it’s eventually consistent and on many occasions it may be overkill when all I’m looking for is a simple in-memory ACI(not D) KV solution which can have 100% of its data replicated on every node.
> mnesia which could be it, but unfortunately requires special attention when initializing tables and making them distributed (which is tricky), handles net splits very badly, needs hacks to resolve conflicts, and does not really support dynamic clusters (additions can be kind of ok, but for instance you can’t remove nodes unless you stop the app).
> …other solutions? In general people end up using Foundation DB or REDIS (which has master-slave replication), so external from the beam. Pity, no?
> So… :) Well I don’t plan to write a database (since ETS is awesome), rather distributing it in a cluster. I’d simply want a distributed ETS solution after all!
> I’ve already started the work and released a version 0.1.0 or ram:
> https://github.com/ostinelli/ram
> Docs are here:
> https://hexdocs.pm/ram
> Please note this is a very early stage. It started as an experiment and it might remain one. So feedback is welcome to decide its future!
> Best,
> r.

We have successfully used https://github.com/jr0senblum/jc with
additional add-on for gen_server and memcached protocols and lazy TTL
reaping (built-in TTL-engine is useless in multimaster mode) as fast
distributed kv (session) storage.


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