×

Adjusting timestamps to preserve update timing information for cached data objects

  • US 6,842,825 B2
  • Filed: 08/07/2002
  • Issued: 01/11/2005
  • Est. Priority Date: 08/07/2002
  • Status: Expired due to Fees
First Claim
Patent Images

1. A method for using timestamps to manage data, the method comprising the following operations:

  • storing some data objects in a cache and other non-cached data objects in a primary storage;

    for each data object stored in the primary storage, writing a current timestamp to the primary storage representing a time that the data object was stored in the primary storage;

    for each data object stored in the cache, placing in the cache an original timestamp corresponding to the data object, the original timestamp representing a time that the data object was stored in the cache;

    writing data objects from the cache and corresponding advanced timestamps to the primary storage, where each advanced timestamp is equal to an original timestamp plus a prescribed time delta;

    responsive to requests to apply a predetermined consistency group formation routine to identified data objects in the primary storage, for each data object, reading the advanced timestamp corresponding to the identified data object and subtracting the time delta therefrom to compute a restored timestamp, and then applying the routine to the identified data object in conjunction with the restored timestamp instead of the advanced timestamp.

View all claims
  • 7 Assignments
Timeline View
Assignment View
    ×
    ×