US Patent 9684687 Multi-phase data expiration path for a database

Each row of data in a first database table is associated with a plurality of time thresholds that indicate, respectively, when a given row of data in the first table is current, stale, or expired. When a given row of data expires, that row is moved from the first table to a second database table that stores expired data. One of the time thresholds indicates a predetermined amount of time that the expired data will be maintained in the second table. Once that threshold expires, that row of data is deleted from the second table. Until then, however, a user may issue queries to access the expired data along with the current data and the stale data.