Hey there,

for a side project I needed to store more than those max. 2gb that the builtin :dets supports and so I created this new pure Elixir library DetsPlus.

It has mostly the same API but is a more Elixir friendly as it supports the Enum protocol and structs/maps!. So you can do Enum.reduce() and friends on it.

When storing maps/structs we have to specify as kepos the field name instead of the element index for tuples. E.g. here an example storing maps with DetsPlus:

{:ok, dets} = DetsPlus.open_file(:example, keypos: :id)
DetsPlus.insert(dets, %{id: 1, value: 42})
[{%id: 1, value: 42}] = DetsPlus.lookup(dets, 1)
# or using the Enum protocol:
[{%id: 1, value: 42}] = Enum.to_list(dets)
:ok =  DetsPlus.close(dets)

It’s using a constant database approach inspired by D.J. Bernsteins CDB library https://cr.yp.to/cdb.html - and so key lookups are extremely efficient even though it’s going to disk. Also when updating the database the whole file is being replaced atomically making DetsPlus great for embedded and Nerves use cases where power might be gone at any time.

Docs: DetsPlus — DetsPlus v2.4.4
Github: GitHub - dominicletz/dets_plus: Pure Elixir disk backed key-value store. · GitHub

Add it to your deps and let me know any feedback!

def deps do
  [
    {:dets_plus, "~> 2.1"}
  ]
end