Techniques for content-based caching in a computer system

• US 8,516,193 B1
• Filed: 11/06/2009
• Issued: 08/20/2013
• Est. Priority Date: 03/30/2006
• Status: Active Grant

• Current Assignee: Pegasystems Incorporated
• Original Assignee: Pegasystems Incorporated
• Inventors: Clinton, John, Martel, Timothy Joseph, Berrachedi, Bachir Mohamed
• Primary Examiner(s): KIM, HONG CHONG
• Application Number:
  US12/590,454
• Time in Patent Office: 1,383 Days
• Field of Search: 711/118, 711/133, 711/159, 711/108, 706/47, 703/3, 726/30, 709/217
• US Class Current: 711/118
• CPC Class Codes: G06F 12/0868 Data transfer between cache memory and other subsystems, e.g. storage devices or host systems
• CPC Class Codes: H04L 67/02 based on web technology, e.g. hypertext transfer protocol [HTTP]
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]
• CPC Class Codes: H04L 67/34 involving the movement of software or configuration parameters network booting or remote initial program loading [RIPL] G06F9/4416
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching

Abstract

Described are techniques for data processing and caching. In response to a client failing to retrieve contents of a data element from a cache location specified by a first data element identifier including a first content-based identifier, the contents of the data element are obtained and stored at a cache location specified by the first data element identifier. The contents of the data element are updated at a second point in time and stored as second contents in the data element source. The data element at the second point in time has a second content-based identifier. In response to the client failing to retrieve the second contents of the data element from a cache location specified by a second data element identifier including the second content-based identifier, the second contents of the data element are obtained and stored at a cache location specified by the second data element identifier.

Claims

1. A computer implemented method for caching comprising:

performing first processing in response to a client failing to retrieve contents of a data element from a cache location specified by a first data element identifier including a first content identifier determined based upon the contents of the data element at a first point in time, said first processing including obtaining the contents of the data element from a data element source and storing the contents of the data element at a cache location specified by the first data element identifier;

updating the contents of the data element at a second point in time to create a second contents of the data element and storing the second contents of the data element at the second point in time in the data element source, said data element at said second point in time having a second content identifier determined based on the second contents of the data element at the second point in time; and

performing second processing in response to the client failing to retrieve the second contents of the data element from a cache location specified by a second data element identifier including the second content identifier, said second processing including obtaining the second contents of the data element from the data element source, and storing the second contents of the data element at a cache location specified by the second data element identifier.

2. The method of claim 1, wherein third processing is performed each time the client fails to retrieve contents for a version of the data element from a cache location specified by an associated data element identifier, said third processing comprising:

obtaining contents for said version of the data element from the data element source; and

storing said contents for said version at the cache location specified by the associated data element identifier, wherein the associated data element identifier includes an associated content identifier determined based upon the contents of the version of the data element.

3. The method of claim 1, further comprising:

storing, at the first point in time, the contents of the data element and associated metadata including at least the first content identifier;

forming the first data element identifier including the first content identifier in response to receiving a request from the client; and

sending a data stream including at least the first data element identifier to said client, wherein said sending occurs prior to said client failing to retrieve the contents of the data element from a cache location specified by the first data element identifier.

4. The method of claim 3, wherein the associated metadata includes a file name, and said first data element identifier is a file path containing the file name.

5. The method of claim 1, wherein at least the first data element identifier includes a portion determined using context information associated with a received request from the client, said first data element identifier being included in a data stream generated in response to the received request.

6. The method of claim 5, wherein the context information includes at least one of a user property associated with a user on behalf of which the received request is issued, a device property associated with a device from which the received request is issued, and a communication channel property.

7. The method of claim 6, wherein the user property is any of security permissions, a disability setting, and locale of the user.

8. The method of claim 6, wherein the device property is any of processor speed, display size, and a keyboard capability.

9. The method of claim 6, wherein the communication channel property is a property of a channel over which the received request is transmitted and includes any of connection speed and connection type between any of the device, the data element source and the cache location.

10. The method of claim 1, wherein the data element source is a storage location on a server.

11. The method of claim 1, wherein at least the first content identifier is a hash value based on the contents of the data element at the first point in time.

12. A computer-implemented method for processing requests received by a server comprising:

processing at a first point in time, in response to receiving a request from a client, one or more rules using a rules engine executing on the server;

generating, as a result of processing the one or more rules, a data stream including a first data element identifier for a data element referenced by the one or more rules, wherein the first data element identifier includes a first content identifier determined based upon contents of the data element at the first point in time;

transmitting the data stream to the client wherein the client subsequently attempts to obtain the data element from a cache location specified by the first data element identifier;

performing first processing in response to the client failing to obtain the contents of the data element from the cache location specified by the first data element identifier, said first processing including retrieving the contents of the data element from a data element source, transmitting the contents of the data element to the client, and storing the contents of the data element at the cache location specified by the first data element identifier;

updating the contents of the data element at a second point in time to create a second contents of the data element and storing second contents of the data element at the second point in time in the data element source, said data element at said second point in time having a second content identifier determined based on the contents of the data element at the second point in time; and

performing second processing in response to the client failing to obtain the second contents of the data element from a cache location specified by a second data element identifier including the second content identifier, said second processing including retrieving the second contents of the data element from the data element source, transmitting the second contents of the data element to the client, and storing the second contents of the data element at the cache location specified by the second data element identifier.

13. The method of claim 12, wherein metadata associated with the data element is stored in the data element source along with the contents of the data element.

14. The method of claim 13, wherein the metadata associated with the data element includes a file name, and any of said first and second data element identifiers is a file path containing the file name.

15. The method of claim 12, wherein the data element at the first point in time includes a reference to a second data element, said reference specifying a third data element identifier including a third content identifier determined based upon contents of the second data element at the first point in time and the method comprising performing third processing in response to the client failing to obtain the contents of the second data element from a cache location specified by the third data element identifier, said third processing including retrieving the contents of the second data element from the data element source, transmitting the contents of the second data element to the client, and storing the contents of the data element at the cache location specified by the third data element identifier.

16. The method of claim 15, wherein, if the contents of the second data element are modified at a particular point in time, the third content identifier and the third data element identifier accordingly change based on modifications to the contents of the second data element at the particular point in time.

17. The method of claim 15, wherein, the third content identifier does not change despite updating the contents of the data element at the second point in time.

18. The method of claim 12, wherein at least one of the one or more rules references a content bundle, said content bundle referencing a plurality of data elements including said data element.

19. The method of claim 18, wherein contents for each of the plurality of data elements is stored in the data element source along with a corresponding content identifier determined based upon contents of said each data element at a particular point in time, and wherein another content identifier is associated with the content bundle, said another content identifier having a value determined based upon contents of said plurality of data elements.

20. The method of claim 19, wherein if the contents of any one of said plurality of data elements are modified, said another content identifier changes accordingly along with the corresponding content identifier that is based upon the contents that are modified.

21. The method of claim 12, wherein the contents of the data element comprise static contents.

22. The method of claim 21, wherein the data element source comprises any of one or more content servers and edge servers.

23. The method of claim 21, wherein any of the cache location specified by the first data element identifier and the cache location specified by the second data element identifier comprise locations on any of one or more content servers and edge servers.

24. The method of claim 22, wherein a first of said one or more content servers or edge servers receives the request from the client and the processing at the first point in time is performed by the server in response to the first of said one or more content, or edge servers transmitting the request to the server.

25. The method of claim 22, wherein the server comprises an application server, said application server returning said data stream to a first of said one or more content servers or edge servers, said data stream then being transmitted to the client.

26. The method of claim 12, wherein at least a portion of the contents of the data element is dynamically generated in response to the request from the client.

27. The method of claim 21, wherein the data element is any of a script, an image file, a video file, and a cascading style sheet.

28. The method of claim 12, wherein said data stream includes contents of a web page.

29. The method of claim 28, wherein said web page is associated with a web page content identifier determined based upon the contents of the web page when said data stream is generated, and said web page is stored at a cache location specified by a web page location identifier including said web page content identifier.

30. A computer implemented method for caching comprising:

storing, at a first point in time, contents of a data element and associated metadata at a data element source, said associated metadata including a file name and a first content identifier based upon the contents of the data element at the first point in time;

determining whether the data element is stored at a cache location identified by a first data element identifier, the first data element identifier including the first content identifier and the file name;

performing first processing in response to determining that the data element is not stored at the cache location identified by the first data element identifier, said first processing including obtaining the contents of the data element from the data element source and storing the contents of the data element at the cache location specified by the first data element identifier;

updating the contents of the data element at a second point in time to create updated contents;

storing, at the data element source, updated contents of the data element at the second point in time and associated metadata including the file name and a second content identifier based on the updated contents of the data element at the second point in time;

determining whether the data element is stored at a cache location identified by a second data element identifier, the second data element identifier including the second content identifier and the file name; and

performing second processing in response to determining that the data element is not stored at the cache location identified by the second data element identifier, said second processing including obtaining the updated contents of the data element from the data element source and storing the updated contents of the data element at the cache location specified by the second data element identifier.

31. A non-transitory computer readable medium comprising executable code stored thereon for data processing and caching, the computer readable medium comprising executable code stored thereon that:

perform first processing in response to a client failing to retrieve contents of a data element from a cache location specified by a first data element identifier including a first content identifier determined based upon the contents of the data element at a first point in time, said first processing including obtaining the contents of the data element from a data element source and storing the contents of the data element at a cache location specified by the first data element identifier;

update the contents of the data element at a second point in time to create a second contents of the data element and store the second contents of the data element at the second point in time in the data element source, said data element at said second point in time having a second content identifier determined based on the second contents of the data element at the second point in time; and

perform second processing in response to the client failing to retrieve the second contents of the data element from a cache location specified by a second data element identifier including the second content identifier, said second processing including obtaining the second contents of the data element from the data element source, and storing the second contents of the data element at a cache location specified by the second data element identifier.

32. A non-transitory computer readable medium comprising executable code stored thereon for processing requests received by a server, the computer readable medium comprising executable code stored that:

process at a first point in time, in response to receiving a request from a client, one or more rules using a rules engine executing on the server;

generate, as a result of processing the one or more rules, a data stream including a first data element identifier for a data element referenced by the one or more rules, wherein the first data element identifier includes a first content identifier determined based upon contents of the data element at the first point in time;

transmit the data stream to the client wherein the client subsequently attempts to obtain the data element from a cache location specified by the first data element identifier;

perform first processing in response to the client failing to obtain the contents of the data element from the cache location specified by the first data element identifier, said first processing including retrieving the contents of the data element from a data element source, transmitting the contents of the data element to the client, and storing the contents of the data element at the cache location specified by the first data element identifier;

update the contents of the data element at a second point in time to create a second contents of the data element and store the second contents of the data element at the second point in time in the data element source, said data element at said second point in time having a second content identifier determined based on the contents of the data element at the second point in time; and

perforin second processing in response to the client failing to obtain the second contents of the data element from a cache location specified by a second data element identifier including the second content identifier, said second processing including retrieving the second contents of the data element from the data element source, transmitting the second contents of the data element to the client, and storing the second contents of the data element at the cache location specified by the second data element identifier.