US Patent 9495398 Index for hybrid database

Providing an index for a database table that includes a first portion of rows stored in a memory device and a second portion of rows stored in a disk device. A request is received relating to a specific row of the database table. An index that includes entries for each row of the database table stored in the memory device and entries for a subset of the rows of the database table stored in the disk device is accessed. A connection is made to the memory device if the specific row is stored in the memory device, and a connection is made to the disk device if the specific row is stored in the disk device. An action related to the specific row is performed based on the received request.