Updating data objects for dynamic application caching

• US 6,772,203 B1
• Filed: 05/09/2002
• Issued: 08/03/2004
• Est. Priority Date: 05/14/1999
• Status: Expired due to Term

• Current Assignee: F5 Networks, Inc. (F5 Incorporated)
• Original Assignee: Pivia, Inc. (F5 Incorporated)
• Inventors: Hoffman, David M., Jordan, Daniel S., Tesh, Robert M., Feiertag, Michael A., Mohan, Sudhir
• Primary Examiner(s): Harrell, Robert B.
• Application Number:
  US10/143,041
• Time in Patent Office: 817 Days
• Field of Search: 709/200, 709/203, 709/219, 370/429, 717/118, 711/100, 711/117, 711/118, 711/133, 711/136
• US Class Current: 709/219
• CPC Class Codes: G06F 16/957 Browsing optimisation, e.g. caching or content distillation

Abstract

In an embodiment, a method comprises receiving a hit rate and a change rate for a data object stored in a cache. The method also includes updating a time-to-live period for the data object stored in the cache based on the hit rate and the change rate for the data object.

Claims

1. A method comprising:

receiving, at a cache server, a request for a data object stored in a data object server;

determining whether a time-to-live period associated with a copy of the data object stored in the cache server has expired, wherein the time-to-live period is based on a hit rate, a change rate and a freshness for the data object; and

transmitting the data object stored in the cache server upon determining the time-to-live period associated with the copy of the data object stored in the cache server has not expired.

2. The method of claim 1, further comprising retrieving the data object stored in the data object server, upon determining that the time-to-live period associated with the copy of the data object stored in the cache server has expired.

3. The method of claim 2, comprising,

generating a new copy of the data object retrieved from the data object server; and

transmitting the data object retrieved from the data object server.

4. The method of claim 3, comprising updating the time-to-live period associated with the data object.

5. The method of claim 4, comprising transmitting characteristics associated with the data object to a different cache server, the characteristics including a hash of the new copy of the data object, and a time when the request was received.

6. The method of claim 5, comprising:

determining if the new copy of the data object is different from the copy of the data object stored in the cache server; and

storing the new copy of the data object in the cache server, upon determining that the new copy of the data object is different.

7. The method of claim 6, wherein the indication that the new copy of the data object is stored in the cache server is used to update the change rate for the data object.

8. The method of claim 5, wherein the time associated with when the request is received is used to update the hit rate for the data object.

9. The method of claim 1, wherein the freshness for the data object comprises a measured freshness value and a freshness value received from an owner of the data object.

10. The method of claim 9, wherein the time-to-live period is adjusted by a scaling factor, wherein the scaling factor is proportional to a difference between the measured freshness value and the freshness value received from the owner of the data object.

11. The method of claim 1, wherein the time-to-live period is shorter when the hit rate is increased for the data object.

12. The method of claim 1, wherein the time-to-live period is shorter when the change rate is increased for the data object.

14. The method of claim 1, comprising,

receiving a freshness value for the data object;

and

generating a scaling factor for the time-to-live period based on the freshness value, wherein the time-to-live period is calculated based on the scaling factor.

15. The method of claim 14, wherein the freshness value comprises a measured freshness value and a freshness value received from an owner of the data object.

16. The method of claim 15, wherein the scaling factor is adjusted by a factor proportional to a difference between the measured freshness value and the freshness value received from the owner of the data object.

13. A method comprising:

receiving a hit rate and a change rate for a data object stored in a cache; and

updating a time-to-live period for the data object stored in the cache based on the hit rate and the change rate for the data object.

17. The method of claim 13, wherein the time-to-live period is shorter when the hit rate is increased for the data object.

18. The method of claim 13, wherein the time-to-live period is shorter when the change rate is increased for the data object.

19. The method of claim 13, wherein the cache is coupled to a data object server and wherein the updating of the time-to-live period occurs when the data object is retrieved, by the cache server, from the data object server.

20. A machine-readable medium that provides instructions, which when executed by a machine, cause said machine to perform operations comprising:

receiving a hit rate and a change rate for a data object stored in a cache; and

updating a time-to-live period for the data object stored in the cache based on the hit rate and the change rate for the data object.

21. The machine-readable medium of claim 20, comprising,

receiving a freshness value for the data object; and

generating a scaling factor for the time-to-live period based on the freshness value, wherein the time-to-live period is calculated based on the scaling factor.

22. The machine-readable medium of claim 21, wherein the freshness value comprises a measured freshness value and a freshness value received from an owner of the data object.

23. The machine-readable medium of claim 22, wherein the scaling factor is adjusted by a factor proportional to a difference between the measured freshness value and the freshness value received from the owner of the data object.

24. The machine-readable medium of claim 20, wherein the time-to-live period is smaller when the hit rate is increased for the copy of the data object.

25. The machine-readable medium of claim 20, wherein the time-to-live period is smaller when the change rate is increased for the copy of the data object.

26. A machine-readable medium that provides instructions, which when executed by a machine, cause said machine to perform operations comprising:

receiving, at a cache server, a request for a data object stored in a data object server;

determining whether a time-to-live period associated with a copy of the data object stored in the cache server has expired, wherein the time-to-live period is based on a hit rate, a change rate and a freshness for the data object; and

transmitting the data object stored in the cache server upon determining the time-to-live period associated with the copy of the data object stored in the cache server has not expired.

27. The machine-readable medium of claim 26, further comprising retrieving the data object stored in the data object server, upon determining that the time-to-live period associated with the copy of the data object stored in the cache server has expired.

28. The machine-readable medium of claim 27, comprising,

generating a new copy of the data object retrieved from the data object server; and

transmitting the data object retrieved from the data object server.

29. The machine-readable medium of claim 28, comprising updating the time-to-live period associated with the data object.

30. The machine-readable medium of claim 26, wherein the time-to-live period is shorter when the hit rate is increased for the data object.

31. The machine-readable medium of claim 26, wherein the time-to-live period is shorter when the change rate is increased for the data object.

32. An apparatus comprising:

a database to store a copy of a data object from a data object server and to associate a time-to-live period with the copy of the data object; and

an inline cache server coupled to the data object server, the inline cache server to process requests for data objects destined for the data object server, the inline cache server to serve the copy of the data object if the time-to-live period has not expired, and the inline cache server to update the time-to-live period for the data object based on a hit rate and a change rate for the data object.

33. The apparatus of claim 32, wherein the time-to-live period is based on a measured freshness value for the data object and a freshness value received from an owner of the data object.

34. The apparatus of claim 33, wherein the time-to-live period is adjusted by a scaling factor, wherein the scaling factor is proportional to a difference between the measured freshness value and the freshness value received from the owner of the data object.

35. The apparatus of claim 32, wherein the time-to-live period is shorter when the hit rate is increased for the data object.

36. The apparatus of claim 32, wherein the time-to-live period is shorter when the change rate is increased for the data object.

37. The apparatus of claim 32, comprising an offline server coupled to the inline cache server, the offline server to generate a policy for the data object, the policy based on the hit rate and the change rate for data object, the policy used to calculate the time-to-live period.

38. A system comprising:

a data object server to store data objects; and

a dynamic application cache server coupled to the data object server, the dynamic application cache server to store a copy of data objects, wherein a time-to-live period is associated with the copies of the data objects, the time-to-live periods based on a hit rate and a change rate for the data objects, the dynamic application cache server coupled to receive requests for the data objects from a number of requesting units,

wherein the dynamic application cache server is to output copies of the data objects to the requesting units, without retrieving the data objects from the data object servers, upon determining that the time-to-live periods for the data objects have not expired.

39. The system of claim 38, wherein the time-to-live periods are based on a measured freshness value for the data object and a freshness value received from an owner of the data object.

40. The system of claim 39, wherein the time-to-live period is adjusted by a scaling factor, wherein the scaling factor is proportional to a difference between the measured freshness value and the freshness value received from the owner of the data object.

41. An apparatus comprising:

request receiving logic coupled to receive a request for a data object stored in a data object server from a requesting unit;

copy verifier logic coupled to the request receiving logic and the data object server, the copy verifier logic to determine if a copy of the data object is stored within a database of the apparatus;

time-to-live verifier logic coupled to the copy verifier logic and the data object server, the time-to-live verifier logic to determine whether the time-to-live period associated with the copy of the data object has expired, wherein the time-to-live period is based on a hit rate, a change rate and a freshness for the data object; and

serving logic coupled to the time-to-live verifier logic, the serving logic to transmit the copy of the data object stored within the database to the requesting unit upon determining the copy of the data object is stored within the database and the time-to-live period has not expired.

42. The apparatus of claim 41, wherein the time-to-liver verifier logic is to transmit a request for the data object to the data object server, upon determining that the time-to-live period associated with the copy of the data object has expired.

43. The apparatus of claim 42, further comprising data object comparison logic coupled to the data object server, the data object comparison logic to receive the data object from the data object server, wherein the data object comparison logic is update the copy of data object and the time-to-live period associated with the copy of the data object within the database, upon determining that the copy of the data object is different from the data object received from the data object server.

44. The apparatus of claim 41, wherein the copy verifier logic is to transmit a request for the data object to the data object server, upon determining that a copy of the data object is not stored within the database.

45. A method comprising:

receiving a hit rate that indicates requests for a data object are transmitted to a data object server;

receiving a change rate that indicates the data object is updated within a cache;

receiving a percentage of the data object served by the cache that is identical to the data object in the data object server; and

generating a time-to-live period for the data object stored in the cache based on the rate that the requests for the data object are transmitted to the data object server, and the rate the data object is updated by the data object server, and the percentage of the data object served by the cache that is identical to the data object stored in the data object server.

46. The method of claim 45, wherein the expiration time is shorter when the hit rate is increased.

47. The method of claim 45, wherein the expiration time is shorter when the change rate is increased.

48. The method of claim 45, wherein the expiration time is generated when the data object is retrieved from the data object server.

49. A machine-readable medium that provides instructions, which when executed by a machine, cause said machine to perform operations comprising:

receiving a hit rate that indicates requests for a data object are transmitted to a data object server;

receiving a change rate that indicates the data object is updated within a cache;

receiving a percentage of the data object served by the cache that is identical to the data object in the data object server; and

generating a time-to-live period for the data object stored in the cache based on the rate that the requests for the data object are transmitted to the data object server, and the data object is updated by the data object server, and the percentage of the data object served by the cache that is identical to the data object stored in the data object server.

50. The machine-readable medium of claim 49, wherein the expiration time is shorter when the hit rate is increased.

51. The machine-readable medium of claim 49, wherein the expiration time is shorter when the change rate is increased.

52. The machine-readable medium of claim 49, wherein the expiration time is generated when the data object is retrieved from the data object server.