A priority queue implementation in Erlang based on Ulf Wiger's comments here.
The priority queue is based on an ordered_set disc_copy table in mnesia.
Keys are constructed as {PriorityLevel::non_neg_integer(), erlang:now()}, which means that entries will be sorted by priority level first, then by insertion time. This avoids possible starvation of entries within a specific priority level.
Priority level 0 is the highest priority, with higher valued levels having lower priority.
Inserts are O(log N). Retrievals are O(1).
Access is serialized via a gen_server.