Method and mechanism for reducing client-side memory footprint of transmitted data

• US 7,089,331 B1
• Filed: 02/29/2000
• Issued: 08/08/2006
• Est. Priority Date: 05/29/1998
• Status: Expired due to Term

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Gollapudi, Sreenivas, Chatterjee, Debashish
• Primary Examiner(s): Donaghue, Larry D.
• Application Number:
  US09/515,674
• Time in Patent Office: 2,352 Days
• Field of Search: 707/2, 707/6, 707/216, 707/101, 709/102, 709/216, 709/217, 709/219, 709/203, 709/247, 711/133, 341/87, 382/244, 718/102
• US Class Current: 709/247
• CPC Class Codes: G06F 16/1748 De-duplication implemented within the file system, e.g. based on file segments de-duplication techniques in storage systems for the management of data blocks G06F3/0641
• CPC Class Codes: G06F 16/284 Relational databases
• CPC Class Codes: G06F 16/9574 of access to content, e.g. by caching
• CPC Class Codes: H04L 67/01 Protocols
• CPC Class Codes: H04L 67/5651 Reducing the amount or size of exchanged application data
• CPC Class Codes: H04L 69/04 Protocols for data compression, e.g. ROHC

Abstract

The present invention is directed to a method and mechanism for reducing the expense of data transmissions between a client and a server. According to an aspect of data prefetching is utilized to predictably retrieve information between the client and server. Another aspect pertains to data redundancy management for reducing the expense of transmitting and storing redundant data between the client and server. Another aspect relates to moved data structures for tracking and managing data at a client in conjunction with data redundancy management.

Claims

1. A process for increasing the efficiency of data transfers between a client and a server comprising:

identifying data requested by a client;

identifying prefetch data, said prefetch data comprising information not immediately requested by said client;

determining the existence of data redundancies in said prefetch data;

obtaining a reduced set of prefetch data based at least in part on the determined existence of data redundancies; and

transmitting the reduced set of prefetch data from the server to the client, said reduced set comprising a smaller memory footprint than said prefetch data;

wherein the existence of said data redundancies is determined by calculating row differences between successive rows in said prefetch data.

2. The process of claim 1 in which calculating said row differences between successive rows in said prefetch data is performed by identifying identical column values for said successive rows.

3. The process of claim 1 in which determining the existence of said data redundancies in said prefetch data is performed by consulting a bitmap corresponding to changes between a first row and a second row of a database table.

4. The process of claim 3 in which consulting said bitmap is performed by evaluating each bit in said bitmap to determine changes between said first row and said second row.

5. The process of claim 1 in which determining the existence of said data redundancies in said prefetch data is performed by creating a bitmap corresponding to changes between a first row and a second row of a database table, said bitmap containing bit values for differences in column values between said first and said second rows.

6. The process of claim 5 in which said first and said second rows are not consecutive rows of prefetch data.

7. The process of claim 6 in which said bitmap is a multidimensional bitmap.

8. The process of claim 1 in which determining the existence of said data redundancies in said prefetch data is performed by identifying multiple copies of an item of information in said prefetch data;

and

the act of transmitting a reduced set of prefetch data comprises sending a single copy of said item that has not changed between a first row and a second row.

9. The process of claim 8 further comprising:

maintaining pointers at said client corresponding to said prefetch data;

pointing multiple ones of said pointers to said single copy in a client cache.

10. A computer program product that includes a medium usable by a processor, the medium having stored thereon a sequence of instructions which, when executed by said processor, causes said processor to execute a process for increasing the efficiency of data transfers between a client and a server, said process comprising:

identifying data requested by a client;

identifying prefetch data, said prefetch data comprising information not immediately requested by said client;

determining the existence of data redundancies in said prefetch data;

obtaining a reduced set of prefetch data based at least in part on the determined existence of data redundancies; and

transmitting the reduced set of prefetch data from the server to the client, said reduced set comprising a smaller memory footprint than said prefetch data;

wherein the existence of said data redundancies is determined by calculating row differences between successive rows in said prefetch data.

11. The computer program product of claim 10 in which calculating said row differences between successive rows in said prefetch data is performed by identifying identical column values for said successive rows.

12. The computer program product of claim 10 in which determining the existence of said data redundancies in said prefetch data is performed by consulting a bitmap corresponding to changes between a first row and a second row of a database table.

13. The computer program product of claim 12 in which consulting said bitmap is performed by evaluating each bit in said bitmap to determine changes between said first row and said second row.

14. The computer program product of claim 10 in which determining the existence of said data redundancies in said prefetch data is performed by creating a bitmap corresponding to changes between a first row and a second row of a database table, said bitmap containing bit values for differences in column values between said first and said second rows.

15. The computer program product of claim 14 in which said first and said second rows are not consecutive rows of prefetch data.

16. The computer program product of claim 15 in which said bitmap is a multidimensional bitmap.

17. The computer program product of claim 10 in which determining the existence of said data redundancies in said prefetch data is performed by identifying multiple copies of an item of information in said prefetch data;

and

the act of transmitting a reduced set of prefetch data comprises sending a single copy of said item that has not changed between a first row and a second row.

18. The computer program product of claim 17 further comprising:

maintaining pointers at said client corresponding to said prefetch data;

pointing multiple ones of said pointers to said single copy in a client cache.

19. The computer program product of claim 10 in which said prefetch data comprises information in a database table.

20. The computer program product of claim 10 in which said prefetch data comprises information associated with a web page.

21. A general purpose computer system comprising at least one server and at least one client, said general purpose computer system configured to increase the efficiency of data transfers between said client and said server, comprising:

said client configured to send a request for data;

said server located remote to said client and configured for receiving said request generated by said client station by;

identify data responsive to said request;

identify prefetch data, said prefetch data comprising information not immediately requested by said client;

determine the existence of data redundancies in said prefetch data;

obtaining a reduced set of prefetch data based at least in part on the determined existence of data redundancies; and

transmit the reduced set of prefetch data from the server to the client, said reduced set comprising a smaller memory footprint than said prefetch data;

wherein said server is configured to determine the existence of said data redundancies by calculating row differences between successive rows in said prefetch data.

22. The computer system of claim 21 in which said server is configured to determine the existence of said data redundancies in said prefetch data by consulting a bitmap corresponding to changes between a first row and a second row of a database table.

23. The computer system of claim 21 in which said server is configured to determine the existence of said data redundancies in said prefetch data by creating a bitmap corresponding to changes between a first row and a second row of a database table, said bitmap containing bit values for differences in column values between said first and said second rows.