Asynchronous information sharing system

• US 6,889,231 B1
• Filed: 12/02/2002
• Issued: 05/03/2005
• Est. Priority Date: 08/01/2002
• Status: Expired due to Term

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Souder, Benny, Downing, Alan, Gawlick, Dieter, Stamos, Jim
• Primary Examiner(s): Coby, Frantz
• Application Number:
  US10/308,924
• Time in Patent Office: 883 Days
• Field of Search: 707/204, 707/205, 707/10, 707/104.1, 707/103.R, 709/203, 709/206, 709/229, 709/226, 709/223, 713/162, 370/351
• US Class Current: 1/1
• CPC Class Codes: G06F 16/27 Replication, distribution or synchronisation of data between databases or within a distributed database system; Distributed database system architectures therefor
• CPC Class Codes: G06F 16/273 Asynchronous replication or reconciliation
• CPC Class Codes: Y10S 707/99944 Object-oriented database structure
• CPC Class Codes: Y10S 707/99945 Object-oriented database structure processing
• CPC Class Codes: Y10S 707/99948 Application of database or data structure, e.g. distributed, multimedia, or image
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

Techniques for sharing information in a wide variety of contexts allows both an explicit capture process and an implicit capture process to add information items to a staging area. An information sharing system supports both implicit and explicit consumption of information items that are stored in the staging area. A rules engine allows users to create and register rules that customize the behavior of the capture processes, the consuming processes, and propagation processes that propagate information from the staging areas to designated destinations. Exactly-once handling of sequence of items is achieved for items maintained in volatile memory. DDL operations are recorded, and operations are asynchronously performed based on the previously-performed DDL operations.

Claims

1. A method for sharing information, the method comprising the steps of:

an explicit capture process adding a first set of one or more information items to a staging area by making an explicit call through an API associated with the staging area;

an implicit capture process automatically adding a second set of one or more information items to said staging area based on events that occur in a system associated with said implicit capture process; and

a consumer process consuming information items that are stored in said staging area.

2. The method of claim 1 where the step of automatically adding a second set of one or more information items is performed by a capture process that inserts information items into the staging area based on the content of log files generated within a database system.

3. The method of claim 2 wherein the staging area is managed by said database system.

4. The method of claim 2 wherein:

the log identifies changes made within said database system; and

the set of one or more information items includes records that reflect a set of said changes.

5. The method of claim 4 wherein:

the set of said changes is a subset of all changes reflected in said logs; and

the capture process selects which changes to reflect in said records based on rules that are indicated in metadata stored within said database system.

6. The method of claim 1 wherein:

the explicit capture process, the implicit capture process and the consuming process are components in an information sharing system; and

the method further comprises the steps of;

the information sharing system receiving rules data that specifies one or more rules that indicate how at least one of said components is to operate; and

registering said rules data by storing, within said information sharing system, metadata that represents said one or more rules;

said at least one component reading said metadata and operating in a manner specified in said metadata.

7. The method of claim 6 wherein the rules data includes rules that indicate how said at least one component is to transform said information items.

8. The method of claim 6 wherein:

the information sharing system includes a database system;

the step of registering said rules data includes storing, within the database system, metadata that represents said one or more rules; and

said at least one component is a process that executes within said database system.

9. The method of claim 1 further comprising the steps of:

the implicit capture process storing, within each information item of said second set of one or more information items, a tag value that indicates that the information item to corresponds to an event that occurred in said system; and

using said tag values to avoid a cycle that would otherwise cause said event to be, re-applied within said system.

10. The method of claim 9 further comprising the steps of:

propagating the information item from said staging area to a second system;

making a change in said second system by applying the event associated with the information item in said second system;

wherein the second system is configured to propagate changes in said second system to said first system; and

wherein the step of using said tag values to avoid a cycle includes, based on the tag value in said information item, preventing said change from being propagated to said first system.

11. The method of claim 1 wherein:

said system is a first system; and

the an implicit capture process executes in a second system that is remote relative to said first system.

12. The method of claim 11 wherein:

the method further comprises the step of communicating a log from the first system to the second system; and

the implicit capture process generating said second set of information items based on information contained in said log.

13. The method of claim 12 wherein:

the first system is a first database system;

the second system is a second database system;

the log is a redo log generated by the first database system; and

the second set of information items identifies changes that were made in said first database system.

14. The method of claim 13 wherein:

the staging area resides in said second database system; and

the method further comprises the step of using an apply process to read said second set of information items from said staging area and to make changes in said second database system based on said second set of information items.

28. A computer-readable medium having stored thereon instructions which, when executed by one or more processors, cause the processors to perform the method recited in any one of claims 1-26 and 27.

15. A method for sharing information, the method comprising the steps of:

an capture process automatically adding a set of one or more information items to said staging area based on events that occur in a first system associated with said capture process; and

an capture process automatically adding a set of one or more information items to said staging area based on events that occur in a first system associated with said capture process; and

the capture process storing, within each information item of said set of one or more information items, a tag value that indicates that the information item corresponds to an event that occurred in said first system;

propagating an information item from said staging area to a second system;

making a change in said second system by applying in said second system the event associated with the information item;

wherein the second system is configured to propagate changes in said second system to said first system; and

using said tag values to avoid a cycle by preventing said change from being propagated to said first system, based on the tag value in said information item.

16. A method for sharing information, the method comprising the steps of

a capture process automatically performing the steps of inspecting redo log files in a first database system;

adding a set of one or more information items to a staging area based on events that are indicated in said redo log files; and

a consuming process automatically processing information items from said staging area by reading information items in said staging area and causing changes to be made in a second database system based on events that are indicated in said redo log files.

17. The method of claim 16 wherein the step of causing changes to be made in said second database includes maintaining in said second database system replicas of one or more database objects in said first database system, wherein said one or more database objects are a subset of replicable objects in said first database system.

18. The method of claim 16 wherein the step of causing changes includes the steps of:

constructing a database command to cause said changes; and

submitting said database command to said second database system.

19. The method of claim 16 wherein the first database system is a different type of database system than said second database system.

20. The method of claim 16 further comprising the steps of:

receiving subscription data that indicates subscribers and information in which the subscribers are interested;

a second consuming process automatically reading information items from said staging area and, based on said subscription data, notifying subscribers that are interested in events associated with the information items.

21. A method for sharing information, the method comprising the steps of:

registering a set of capture rules within a database system;

registering a set of propagation rules within said database system;

based on said set of capture rules, determining which events that occur within said database system are to be captured;

capturing said events by storing information about said events in a staging area;

based on said set of propagation rules, determining how to propagate information from said staging area; and

propagating information from said staging area based on said set of propagation rules.

22. The method of claim 21 wherein further comprising the steps of:

registering a set of apply rules;

receiving said information propagated from said staging area; and

applying said information received from said staging area based on said set of apply rules.

23. The method of claim 21 wherein the step of capturing said events includes reading logs generated by said database system, and selectively storing in said staging area information about events identified in said logs.

24. The method of claim 21 wherein:

the step of propagation includes propagating said information to a second staging area; and

the method further includes the step of applying changes identified in said second staging area to a second database system.

25. The method of claim 24 further wherein:

the method further comprises the step of registering a set of apply rules; and

the step of applying changes is performed based on said set of apply rules.

26. The method of claim 24 further wherein:

the method further comprises the step of registering a user procedure; and

the step of applying changes is performed based on said user procedure.

27. A method for sharing information, the method comprising the steps of:

a capture process adding a first set of one or more information items to a staging are;

an apply process automatically reading information items from said staging are and selectively consuming said information items; and

an explicit dequeue process consuming an information item from said staging area by making a explicit call to an API associated with said staging area.