Asynchronous actions using flashback

• US 20050125430A1
• Filed: 01/12/2005
• Published: 06/09/2005
• Est. Priority Date: 08/01/2002
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Gawilick, Dieter, Souder, Benny, Downing, Alan, Stamos, Jim
• Granted Patent: US 7,814,067 B2
• Time in Patent Office: Days
• 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 are disclosed for sharing information in a wide variety of contexts. An information sharing system is described that allows both an explicit capture process and an implicit capture process to add information items to a staging area. Further, the information sharing system supports both implicit and explicit consumption of information items that are stored in said staging area. A rules engine is provided to allow 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. Techniques are also described for achieving exactly-once handling of sequence of items, where the items are maintained in volatile memory. Techniques are also provided for recording DDL operations, and for asynchronously performing operations based on the previously-performed DDL operations.

Claims

1. A method for responding to a change made in a system, the method comprising the steps of:

assigning a change time to said change;

generating a record of said change, wherein the step of generating said record is performed asynchronously relative to when the change is made;

reading said record of said change, wherein the step of reading said record is performed asynchronously relative to when the record is generated;

executing a flashback query, wherein the flashback query processes data from said system at an access time that is based on said change time; and

determining an action to perform in response to said change based on results of said flashback query.

2. The method of claim 1 wherein:

said system is a database system;

the step of generating a record is performed based on information read from a log file that is generated by said database system.

3. The method of claim 1 wherein:

the step of generating said record is performed by a capture process that causes said record to be stored in said staging area; and

the step of reading said record is performed by a consuming process that consumes records stored in said staging area.

4. A machine-readable medium carrying one or more sequences of instructions for responding to a change made in a system, wherein execution of the one or more sequences of instructions by one or more processor cases the one or more processors to perform the steps of:

assigning a change time to said change;

generating a record of said change, wherein the step of generating said record is performed asynchronously relative to when the change is made;

reading said record of said change, wherein the step of reading said record is performed asynchronously relative to when the record is generated;

executing a flashback query, wherein the flashback query processes data from said system at an access time that is based on said change time; and

determining an action to perform in response to said change based on results of said flashback query.

5. The machine-readable medium as recited in claim 4 wherein:

said system is a database system;

the step of generating a record is performed based on information read from a log file that is generated by said database system.

6. The machine-readable medium as recited in claim 4 wherein

the step of generating said record is performed by a capture process that causes said record to be stored in said staging area;

and

the step of reading said record is performed by a consuming process that consumes records stored in said staging area.