I would like to pool my database connections in an application I'm writing, and so far haven't found any prior art on the subject (besides this[1]). I was wondering if:

* There's a package somewhere that does this

* Others have implemented it and have suggestions

* There's some big gotchas

The stackoverflow that I linked to gives one approach to this that seems valid. My original thought on an implementation was to use a Chan. That way:

* When a connection is released, is goes to the end of the pool, so connections get used evenly (not sure if this actually matters in practice).

* If a process dies and for some reason doesn't return its connection, there shouldn't be a problem. Of course, I'd use bracket, so such a situation should never arise anyway.

* Keep the coding against MVar to a minimum to avoid normal multi-threaded pitfalls.

I'm using HDBC in this case, but I don't think I'll be using any HDBC-specific code.

Thanks,

Michael

[1] http://stackoverflow.com/questions/1141677/concurrent-db-connection-pool-in-haskell