What is In-Memory OLTP (Hekaton) in SQL Server?

In-Memory OLTP stores tables in memory-optimized structures for high concurrency and low latency.

Hekaton uses latch-free data structures, optimistic concurrency, and versioning instead of locks. Data is stored in memory-optimized tables with durable or non-durable modes. It uses checkpoint files and delta files for persistence. It is ideal for high-throughput OLTP workloads.