I have a requirement to create and maintain a ledger of orders. Thousands and of them, with many updates per second. It will operate in a high-speed environment: currently in single-digit mcs range; I'd like to see it in high nanos. - Must be thread-safe - Multiple threads and processes will be reading and writing concurrently - Said ledger will be updated with algos (no GUI order input) Noodling on how to best implement this... what data structure makes sense here? 1. A vector of pointers or references to orders? 2. A hash table? 3. Caching? I fear race conditions. 4. Database of some kind? I fear perf penalties. I was thinking a separate thread or process, dedicated to holding the structure in memory, with accessor and mutator methods? Make every effort to stick with atomic operations, to perf penalties associated with locking? Feedback and/or advice welcome. Thanks.