Partial evaluation of rule sets

• US 8,005,802 B2
• Filed: 05/30/2003
• Issued: 08/23/2011
• 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: Lu, Edwina, Kaluskar, Sanjay, Bhatt, Neerja, Wang, Wei, Wong, Lik, Stamos, James
• Primary Examiner(s): Mofiz; Apu M
• Assistant Examiner(s): Pyo; Monica M
• Application Number:
  US10/452,850
• Publication Number:
  US 20040030707A1
• Time in Patent Office: 3,007 Days
• Field of Search: 707/1, 707/100, 707/101, 707/10, 707/200, 707/999.009, 707999101-999102, 707/694
• US Class Current: 707/694
• 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: Y10S 707/99939 Privileged access
• CPC Class Codes: Y10S 707/99942 Manipulating data structure, e.g. compression, compaction, compilation
• CPC Class Codes: Y10S 707/99943 Generating database or data structure, e.g. via user interface

Abstract

Described herein are various approaches that allow rules to be used to specify actions, that alleviate the complexity and burden of developing and maintaining rules in a rules-based messaging system, and that provide more efficient ways of evaluating rules. The approaches allow rules to specify user-defined transformation functions for transforming messages, to specify when and how to perform row migration, and to specify other types of actions. Rules are grouped into rule sets. Several types of rule sets, referred to as positive and negative rule sets, allow users to use rules that are less complex to develop and maintain. Rule sets are evaluated more efficiently by attempting to evaluate the rule set with less information than is needed to evaluate all the rules in the rule set. Also, the results of rules evaluations that are based on a set of values are cached for later retrieval.

Claims

1. A method for evaluating a set of rules, the method including the steps of:

when at least one value of a plurality of values referenced by rules in said set of rules is available, but before a subset of said plurality of values is available, making a determination of whether said set of rules DOES or DOES NOT necessarily evaluate to a particular result;

wherein each rule of said set of rules contains one or more rule conditions;

wherein for each rule condition of each rule of said set of rules, the plurality of values includes each value referenced by said each rule condition;

wherein each value of said plurality of values is referenced by a rule condition of a rule of said set of rules;

when said determination of whether said set of rules DOES or DOES NOT necessarily evaluate to a particular result is that said set of rules DOES NOT necessarily evaluate to a particular result;

generating one or more data structures that (1) hold said subset of said plurality of values and that (2) are needed to further evaluate said set of rules; and

evaluating said set of rules based on said subset of said plurality of values;

when said determination of whether said set of rules DOES or DOES NOT necessarily evaluate to a particular result is that said set of rules DOES necessarily evaluate to a particular result, then forgoing generating said one or more data structures; and

wherein each step of said steps is executed by one or more computers.

2. The method of claim 1, further including for when said determination of whether or not said set of rules necessarily evaluate to a particular result is that said set of rules DOES NOT necessarily evaluate to a particular result, storing in a cache an evaluation result that denotes that said set of rules does not necessarily evaluate to a particular result based on said subset of said plurality of values, wherein said evaluation result is stored in said cache in a manner that associates said evaluation result with said subset of said plurality of values.

3. The method of claim 2, wherein the step of storing in a cache an evaluation result includes:

generating a hash value based on the subset of said plurality of values; and

storing the evaluation result in association with said hash value.

4. The method of claim 2, further including:

for another evaluation of said set of rules, determining that the cache stores said evaluation result that denotes that said set of rules does not necessarily evaluate to a particular result; and

in response to determining that the cache stores said evaluation result that denotes that said set of rules does not necessarily evaluate to a particular result, forgoing making a determination of whether said set of rules necessarily evaluate to a particular result.

5. The method of claim 1, wherein said plurality of values includes first one or more values reflecting a change to a column of a table stored at a database server.

6. The method of claim 5, wherein said subset of said plurality of values are read from a record of a redo log reflecting a change to a row in a table stored at a database server.

13. The method of claim 1, wherein said subset of said plurality of values are read from a record of a redo log reflecting a change to a row in a table stored at a database server.

7. A computer-readable storage medium storing one or more sequences of instructions for evaluating a set of rules, said one or more instructions, which, when executed by one or more processors, causes the one or more processors to perform steps of:

when at least one value of a plurality of values referenced by rules in said set of rules is available, but before a subset of said plurality of values is available, making a determination of whether said set of rules DOES or DOES NOT necessarily evaluate to a particular result;

wherein each rule of said set of rules contains one or more rule conditions;

wherein for each rule condition of each rule of said set of rules, the plurality of values includes each value referenced by said each rule condition;

wherein each value of said plurality of values is referenced by a rule condition of a rule of said set of rules;

when said determination of whether said set of rules DOES or DOES NOT necessarily evaluate to a particular result is that said set of rules DOES NOT necessarily evaluate to a particular result;

generating one or more data structures that (1) hold said subset of said plurality of values and that (2) are needed to further evaluate said set of rules; and

evaluating said set of rules based on said subset of said plurality of values; and

when said determination of whether said set of rules DOES or DOES NOT necessarily evaluate to a particular result is that said set of rules DOES necessarily evaluate to a particular result, then forgoing generating said one or more data structures.

8. The computer-readable storage medium of claim 7, the steps further including for when said determination of whether or not said set of rules necessarily evaluate to a particular result is that said set of rules DOES NOT necessarily evaluate to a particular result, storing in a cache an evaluation result that denotes that said set of rules does not necessarily evaluate to a particular result based on said subset of said plurality of values, wherein said evaluation result is stored in said cache in a manner that associates said evaluation result with said subset of said plurality of values.

9. The computer-readable storage medium of claim 7, wherein the step of storing in a cache an evaluation result includes:

generating a hash value based on the subset of said plurality of values; and

storing the evaluation result in association with said hash value.

10. The computer-readable storage medium of claim 7, the steps further including:

for another evaluation of said set of rules, determining that the cache stores said evaluation result that denotes that said set of rules does not necessarily evaluate to a particular result; and

in response to determining that the cache stores said evaluation result that denotes that said set of rules does not necessarily evaluate to a particular result, forgoing making a determination of whether said set of rules necessarily evaluate to a particular result.

11. The computer-readable storage medium of claim 7, wherein said plurality of values includes first one or more values reflecting a change to a column of a table stored at a database server.

12. The computer-readable storage medium of claim 11, wherein said subset of said plurality of values are read from a record of a redo log reflecting a change to a row in a table stored at a database server.

14. The computer-readable storage medium of claim 7, wherein said subset of said plurality of values are read from a record of a redo log reflecting a change to a row in a table stored at a database server.