Method, System and Server of Removing a Distributed Caching Object

• US 20130145099A1
• Filed: 08/23/2011
• Published: 06/06/2013
• Est. Priority Date: 08/26/2010
• Status: Active Grant

• Current Assignee: Alibaba Group Holding Ltd.
• Original Assignee: Alibaba Group Holding Ltd.
• Inventors: Liu, Gang, Ren, Qing, Zhang, Wensong
• Granted Patent: US 8,769,208 B2
• Time in Patent Office: Days
• US Class Current: 711/133
• CPC Class Codes: G06F 12/12 Replacement control
• CPC Class Codes: G06F 12/122 of the least frequently used [LFU] type, e.g. with individual count value
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching
• CPC Class Codes: H04L 67/5682 Policies or rules for updating, deleting or replacing the stored data

Abstract

The present disclosure discloses a method, a system and a server of removing a distributed caching object. In one embodiment, the method receives a removal request, where the removal request includes an identifier of an object. The method may further apply consistent Hashing to the identifier of the object to obtain a Hash result value of the identifier, locates a corresponding cache server based on the Hash result value and renders the corresponding cache server to be a present cache server. In some embodiments, the method determines whether the present cache server is in an active status and has an active period greater than an expiration period associated with the object. Additionally, in response to determining that the present cache server is in an active status and has an active period greater than the expiration period associated with the object, the method removes the object from the present cache server. By comparing an active period of a located cache server with an expiration period associated with an object, the exemplary embodiments precisely locate a cache server that includes the object to be removed and perform a removal operation, thus saving the other cache servers from wasting resources to perform removal operations and hence improving the overall performance of the distributed cache system.

Claims

1. A method of removing a distributed cache object, comprising:

receiving a removal request, the removal request including an identifier of an object;

applying Hashing to the identifier of the object to obtain a Hash result value of the identifier;

locating a corresponding cache server based on the Hash result value and rendering the corresponding cache server to be a present cache server;

determining whether the present cache server is in an active status and has an active period greater than an expiration period associated with the object; and

in response to determining that the present cache server is in an active status and has an active period greater than the expiration period associated with the object, removing the object from the present cache server.

2. The method as recited in claim 1, further comprising:

in response to determining that the active period is less than the expiration period, removing the object from the present cache server; and

shifting from the present cache server to a next cache server, rendering the next cache server as the present cache server, and returning to the act of determining whether the present cache server is in an active status and has an active period greater than an expiration period associated with the object.

3. The method as recited in claim 2, wherein upon locating the corresponding cache server based on the Hash result value, the method further comprises:

if the present cache server is in an inactive status, determining whether an inactive period of the present cache server is greater than the expiration period of the object.

4. The method as recited in claim 3, further comprising:

if the inactive period is greater than the expiration period, shifting from the present cache server to the next cache server, rendering the next cache server as the present cache server, and returning to the act of determining whether the present cache server is in an active status and has an active period greater than an expiration period associated with the object.

5. The method as recited in claim 3, further comprising:

if the inactive period is not greater than the expiration period, recording the identifier and performing the act of shifting from the present cache server to a next cache server.

6. The method as recited in claim 5, further comprising:

if the present cache server is resumed to the active status, removing the object based on the recorded identifier.

7. The method as recited in claim 1, further comprising setting up a status table of cache servers in advance.

8. The method as recited in claim 7, further comprising storing a time stamp of the last status change of each cache server and a current status of each cache server in the status table, the time stamp being used for determining a time duration of the current status of a respective cache server.

9. A system of removing a distributed caching object, comprising a removal server and multiple cache servers, wherein:

the cache servers are configured to cache objects that are accessed by users; and

the removal server is configured to;

receive a removal request, the removal request including an identifier of an object,

apply consistent Hashing to the identifier of the object to obtain a Hash result value of the identifier,

locate a corresponding cache server based on the Hash result value and render the corresponding cache server to be a present cache server,

determine whether the present cache server is in an active status and has an active period greater than an expiration period associated with the object, and

in response to determining that the present cache server is in an active status and has an active period greater than the expiration period associated with the object, remove the object from the present cache server.

10. The system as recited in claim 9, wherein in response to determining that the active period is less than the expiration period, the removal server is further configured to remove the object from the present cache server, shift from the present cache server to a cache server that is next in an order, render the next cache server as the present cache server, and return to the act of determining whether the present cache server is in an active status and has an active period greater than the expiration period of the object.

11. The system as recited in claim 10, wherein the removal server is further configured to determine whether the active period of the present cache server is greater than the expiration period of the object if the present cache server is in an inactive status, shift from the present cache server to the cache server that is next in the order and render the next cache server as the present cache server if the inactive period is greater than the expiration period, and return to the act of determining whether the present cache server is in an active status and has an active period greater than the expiration period of the object.

12. The system as recited in claim 11, wherein the removal server is further configured to record the identifier if the inactive period is not greater than the expiration period, perform the act of shifting from the present cache server to a next cache server, and remove the object based on the recorded identifier after the present cache server is resumed to an active status.

13. The system as recited in claim 9, wherein the removal server is further configured to set up a status table of cache servers.

14. The system as recited in claim 13, wherein the removal server is further configured to store a time stamp of the last status change of each cache server and a current status of each cache server in the status table, and wherein the time stamp is used for determining a time duration about how long corresponding cache server is in the current status.

15. A removal server, comprising:

a receiving unit configured to receive a removal request, where the removal request includes an identifier of an object;

a computation unit configured to apply consistent Hashing to the identifier of the object to obtain a Hash result value of the identifier;

a locating unit configured to locate a corresponding cache server based on the Hash result value and render the corresponding cache server to be a present cache server;

a determination unit configured to determine whether the present cache server is in an active status and has an active period greater than an expiration period associated with the object; and

a removal unit configured to remove the object from the present cache server in response to determining that the present cache server is in an active status and has an active period greater than the expiration period associated with the object.

16. The removal server as recited in claim 15, wherein the removal unit is further configured to remove the object from the present cache server in response to determining that the active period is less than the expiration period, and wherein the removal server further comprises a shifting unit configured to shift from the present cache server to a next cache server, render the next cache server as the present cache server, and trigger the determination unit.

17. The removal server as recited in claim 16, wherein the determination unit is further configured to determine whether an inactive period of the present cache server is greater than the expiration period of the object if the present cache server is in an inactive status, and if the inactive period of the present cache server is greater than the expiration period, the shifting unit is further configured to shift from the present cache server to a next cache server, render the next cache server as the present cache server, and trigger the determination unit.

18. The removal server as recited in claim 17, further comprising:

a recording unit configured to record the identifier and trigger the shifting unit if the inactive period is not greater than the expiration period;

wherein the removal unit is further configured to remove the object based on the recorded identifier after the present cache server returns to the active status.

19. The removal server as recited in claim 15, further comprising a setup unit configured to set up a status table of cache servers in advance.

20. The removal server as recited in claim 19, further comprising a storage unit configured to store a time stamp of the last status change of each cache server and a current status of each cache server in the status table, the time stamp being used for determining a time duration of a current status of a respective cache server.