If screaming speed in data access is the most important thing in your life, SQL Server's durable in-memory, memory-optimized tables are your answer. They were good in SQL Server 2014 and they're even ...

Facebook open sources C++ F14 hash table Making fast hash tables in programming, which don't cause collision trouble, is one of computing's holy grails. Facebook thinks it's created a good one.

There is no reason a hash table can't be stored on disk just as easily as in memory.<BR><BR>If you can use open addressing, it is trivial, you can even just memory map the table if you want.