Concurrent data structure design

Question

I am trying to come up with the best data structure for use in a high throughput C++ server. The data structure will be used to store anything from a few to several million obje

Answer 1

Apologies for the double-answer...

Since writes are fairly rare, you really should consider using STM instead of locking. STM is a form of optimistic locking, which means that it is heavily biased in performance toward collision-free systems (a.k.a. fewer writes). By contrast, pessimistic locking (lock-write-unlock) is optimized for collision-heavy systems (a.k.a. lots of writes). The only catch with STM is it almost demands that you make use of immutable data structures within the TVar cells, otherwise the whole system breaks down. Personally, I don't think this is a problem since a decent immutable data structure is going to be just as fast as a mutable one (see my other answer), but it's worth considering.