Dual-component state token with state data direct access index for systems with high transaction volume and high number of unexpired tokens

• US 20050256822A1
• Filed: 05/13/2004
• Published: 11/17/2005
• Est. Priority Date: 05/13/2004
• Status: Active Grant

• Current Assignee: SAP SE
• Original Assignee: International Business Machines Corporation
• Inventors: Hollingsworth, James Lewis
• Granted Patent: US 7,512,693 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/2308 Concurrency control transaction processing G06F9/466
• CPC Class Codes: Y10S 707/99931 Database or file accessing

Abstract

Access to state data by a client process such as state data in an Online Transaction Processing arrangement is controlled through generation of and exchanging of a dual-component token. The first component of the token is an Index value which indirectly points to a block of state data assigned to process or user. The second component of the token is a sequence value, such as a Random Unique Sequence value, which is also associated with the block of state data for a process. With each transaction request, a user process provides the token to the OLTP server, which then verifies the sequence numbers of the state data and the token match before allowing access to the data.

Claims

1. A logical device for managing access by a user of state data associated with a logical process, said device comprising:

a dual-component token generator configured to generate a dual-component access token, said token comprising at least an index value and a sequence value;

an exchange mechanism adapted to exchange said dual-component token between a user of state data and a repository for said state data, said dual-component token being provided by said generator to said user of state data, and said dual-component token being provided to said repository in association with a request for access to said state data;

a repository access controller configured to receive said request for access to said state data, to examine said dual-component access token, and to allow or disallow access by said user to said data based upon said index value and said sequence value.

2. The device as set forth in claim 1 further comprising a State Data Index array having one or more entries, each entry comprising a status indicator and an address value, said address value pointing to a block of data for a State Data Block, and wherein said dual-component token comprises an index value associated correlating to an entry in a State Data Index array.

3. The device as set forth in claim 2 wherein said status indicator comprises a status indication selected from the group of “

reserved”

, “

available”

, and “

in use”

.

4. The device as set forth in claim 2 further comprising a State Data Available array configured to store one or more index values associated with entries in said State Data Index array which are available for assignment to a user.

5. The device as set forth in claim 1 wherein said sequence value comprises a sequence value which is pseudo-random in nature.

6. The device as set forth in claim 5 wherein said pseudo-random sequence value is produced by modifying a previously used sequence value with a random value.

7. The device as set forth in claim 1 wherein said exchange mechanism is further configured to transmit, receive, and convert said dual-component tokens such that each token is exchanged in a computer displayable format.

8. The device as set forth in claim 7 wherein said displayable format comprises a text encoding format.

9. The device as set forth in claim 1 wherein said repository access controller is further configured to compare a sequence value associated with a block of state data and a sequence value received from a user, and to allow access to said state data only upon a match of said sequence values.

10. The device as set forth in claim 9 wherein said repository access controller is further configured to, responsive to determination that said sequence values do not match, deny access by said user to said state data, purge said state data, and change a status indicator to “

available”

in a State Data Index array associated with said state data.

11. The device as set forth in claim 1 wherein said repository access controller is further configured to deny access by a user to state data responsive to receiving a request for access to state data which is indicated as being “

in use”

or “

available”

in a State Data Index array.

12. The device as set forth in claim 1 wherein said repository access controller is further configured to periodically check an expiration indicator for a block of state data, and responsive to a system time or system date meeting or exceeding said expiration, purging said state data block, and changing a status indicator of said purged state data block to “

available”

.

13. A computer-readable medium comprising a data structure for controlling access to state data by users of said state data, said data structure comprising:

a State Data Index array having one or more entries, each entry having a status indicator and an address value;

one or more blocks of state data, each block being associated with an address value corresponding to an entry in said State Data Index array, and each block having a Random Unique Sequence value associated with it; and

a dual-component token having an Index component an a Random Unique Sequence component, said token being associated with a user or owner of a block of state data wherein said Index component points to an entry in said State Data Index array which contains the address associated with the owned state data block, and wherein said Random Unique Sequence component matches the Random Unique Sequence value associated with said owned state data block.

14. The medium as set forth in claim 13 further comprising a State Data Available array containing one or more Index values which point to entries in said State Data Index array corresponding to available, unowned state data blocks.

15. The medium as set forth in claim 13 wherein said dual-component token is encoded into a displayable format for exchange between a state data repository and a user of said state data.

16. The medium as set forth in claim 15 wherein said displayable format is a text encoding format.

17. The medium as set forth in claim 13 wherein said status indicators are selected from the group of “

available”

, “

in use” and

“

reserved”

.

18. A method of managing access by a user of state data associated with a logical process, said method comprising the steps of:

initially generating a dual-component token generator upon allocation of a block of state data to a logical process, said token comprising at least an index component and a sequence component, and associating said sequence value with said allocated block of state data in a repository;

providing said token to a logical process;

receiving a request from a logical process for access to said state data, said request including a dual-component token;

verifying the sequence value contained in said received token against the sequence value associated with an indicated block of state data in said repository, said indicated block of state data being determined in part by said Index component of the received token; and

allowing access to said state data responsive to finding a match between said sequence values.

19. The method as set forth in claim 18 further comprising providing a State Data Index array having one or more entries, each entry comprising a status indicator and an address value, said address value pointing to a block of data for a State Data Block, wherein said dual-component token index component is correlates to an entry in said State Data Index array.

20. The method as set forth in claim 19 wherein said status indicator comprises a status indication selected from the group of “

reserved”

, “

available”

, and “

in use”

.

21. The method as set forth in claim 19 further comprising providing a State Data Available array configured to store one or more index values associated with entries in said State Data Index array which are available for assignment to a user.

22. The method as set forth in claim 18 wherein said step of generating a sequence value comprises generating a sequence value which is pseudo-random in nature.

23. The method as set forth in claim 22 wherein said pseudo-random sequence value is produced by modifying a previously used sequence value with a random value.

24. The method as set forth in claim 18 wherein said steps of providing said token to a logical process and receiving a token associated with an access request further comprise conversion of said tokens to and from a computer displayable format.

25. The method as set forth in claim 24 wherein said displayable format comprises a text encoding format.

26. The method as set forth in claim 18 wherein said step of verifying said received sequence number against a sequence number of a block of state data comprises, responsive to determination that said sequence values do not match, denying access to said state data block, purging said state data, and changing a status indicator to “

available”

in a State Data Index array associated with said state data.

27. The method as set forth in claim 18 further comprising denying access by a user to state data responsive to receiving a request for access to state data which is indicated as being “

in use”

or “

available”

in a State Data Index array.

28. The method as set forth in claim 18 further comprising periodically checking an expiration indicator for each block of state data, and responsive to a system time or system date meeting or exceeding said expiration, purging a state data block, and changing a status indicator of said purged state data block to “

available”

.