Patent ID: 8521695

Claim:
A computer-implemented data recovery method comprising: creating a snapshot of a source database, the source database comprising a plurality of files, the snapshot comprising a side file for each of the plurality of files in the source database, each side file having the same logical size as the corresponding file in the source database, wherein each side file stores portions of the data in the corresponding file from the source database that was changed; storing the side files as sparse files, wherein each sparse file comprises an allocation of storage for storing each portion of data in the corresponding side file, not include an allocation of storage for the remaining portions of the side file representing unchanged data from the source database; creating a side page table that stores indications of whether or not a given side file includes valid data and which includes an in-memory bitmap which holds at least one bit for each page in the given side file; and using the sparse files and the side page table to restore the source database to an earlier state.