Patent ID: 8527462

Claim:
A computer-readable storage medium configured with data and with instructions that when executed by at least one processor causes the processor(s) to perform a process for accessing a version of database content as it existed at a previous point in time (the “as-of time”), the process comprising the steps of: acquiring a database snapshot based on a database; undoing modifications of database content which were made after the as-of time, said undoing step being performed computationally in the acquired snapshot at a page level, said undoing step computationally producing an electronically accessible as-of snapshot which is a snapshot of the database as it existed at the as-of time; and handling an as-of query using a page which contains information responsive to the query, wherein the as-of query handling step comprises at least one of the following: determining that the page which contains information responsive to the query is present in a sparse page file of the as-of snapshot; determining that the page which contains information responsive to the query is not yet present in a sparse page file of the as-of snapshot, reading the page from the database, undoing modifications of the page back to the as-of time to produce an as-of page, and writing the as-of page to the sparse page file of the as-of snapshot; or sharing sparse file cache content among different as-of snapshots.