To address the need for extreme OLTP performance on commodity multi-core hardware supporting large amounts of memory, SAP ASE is re-architected to tightly integrate an In-Memory Row Store (IMRS) within the existing database engine. The IMRS is both a store and a caching layer to host "hot" rows in-memory, in a row-oriented format. The IMRS is an extension to the traditional buffer-cache which deals with data in a page-oriented storage format (referred to as the page-store). Data in individual tables marked as IMRS-enabled can be fully memory-resident or can straddle the page store and the IMRS. Cold data in the IMRS is organically identified, harvested, and "packed" back to the page store. SQL statements and transactions can access data transparently from both stores for the same table. All Transact-SQL capabilities and language constructs are supported with no application or stored procedure code changes required. Full durability for in-memory data is provided, including support for backup and restore of database archives and periodic transaction dumps. The high-level system design supporting this architecture, along with experimental results and performance benefits is presented.