I've tested out a couple of ways of storing a queue structure and
wondered if others had some better ideas.  I tried a berkeleydb based
queue using it's native queue structure, which gives the best
performance so far but it's for unix only.  I also have a file based
queue where every message is just stored in a sequentially numbered
file.  Almost as fast as berkeleydb and works anywhere.  Just for
giggles I tried sqlite, and then immediately deleted it.  6-8 tps with
sqlite compared to around 1000 with berkeleydb/flat files.

Another alternative I was thinking of is a single file storage of some
type, maybe fixed length or even variable length records.  Something
that's portable.  But I'm thinking that could get complicated fairly
quickly.

Any other ideas?