RankEx

A ranking/leaderboard library for Elixir based on ETS.

It maps score (integer or float) to a integer id or UUID along with any other data (name of the ranker).

It's leveraged on ETS ordered set once it can also order some kinds of records with a tuple as key.

This way all operations regarding sorting is given for granted within a bulletproof cache.

For performance reasons, update and delete operations require the previous score which allows this mapping (id->score) to be stored in users cache without duplicity.

Supports:

• Fast insertion
• Fast update
• Fast delete
• Position by score (thousand reads in 300ms) or id
• Detail field that might be used for rank names or other info
• All with operation for tied score
• Multiple tables
• Top N results in different formats:
  • :tuples : [{{score, id}, detail}, ...]
  • :map_list : [%{id: id, detail: detail, score: score}, ...]
  • :position_map : %{1: %{id: id, detail: detail, score: score}, 2: ...}
  • :score_position_map : %{score_value => %{id: id, detail: detail, position: position}, ...}

Benchmarking

insert/3 for 10000 items: 30ms

After inserting one million records:

delete/2 for 10000 items: 7ms update/4 for 10000 items: 37ms position_in/2 for 1000 items: 272ms

Running on Intel(R) Core(TM) i7-8550U CPU @ 1.80GHz and DDR4 2400 MT/s

Installation

If available in Hex, the package can be installed by adding benchmarking to your list of dependencies in mix.exs:

def deps do
  [
    {:rankex, "~> 0.1.0"}
  ]
end

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/benchmarking.