Patent ID: 8924350

Claim:
A computer system including a processor and instructions stored on a non-transitory computer-readable storage medium, the computer system comprising: a database comparator to identify a first portion of an original user database of an original system for upgrade; a user database module to define, at a shadow system, a shadow user database having a structure defining an upgrade to a structure of the first portion of the original user database; a database replicator to, perform at least one first transfer of data from the first portion of the original user database into the structure of the shadow user database during an uptime of the original system, record, in a log, changes to data in the original user database corresponding to the at least one first transfer of data from the first portion of the original user database during the uptime of the original system, replicate the changes to the data in the structure of the shadow user database during the uptime of the original system, identify a second portion of the original user database of the original system for aliasing in the shadow system, reference the second portion of the original user database as an alias database on the shadow system during an uptime of the original system, and perform a final transfer of data from the first portion of the original user database into the structure of the shadow user database during a downtime of the original system; and an upgrade transfer module to replace the first portion of the original user database with the shadow user database after the final transfer of data has been performed, and remove the alias database during a downtime of the original system.