The priority queue implementations implement a subset of the stdlib Erlang queue interface as seen in the implementation used by both Riak and RabbitMQ.

The implementations:

• priority_queue (fastest for any priorities when only using a single priority at a time)
• pqueue (fastest for 41 priorities, -20 (high) to 20 (low), when using 2 or more priorities at the same time)
• pqueue2 (slower heap implementation)
• pqueue3 (faster than pqueue2 and priority_queue when using 64 or more priorities at the same time)
• pqueue4 (slightly slower than pqueue but fastest for allowing 257 priorities, -128 (high) to 128 (low), i.e., fastest when using 42 or more priorities at the same time)

The latest results are here, with the benchmark here.

Michael Truog (mjtruog [at] gmail (dot) com)

• Jesper Louis andersen (PropEr integration and testing)
• Ulf Wiger (suggestions and insight)

BSD