Efficient partitioning technique while managing large XML documents

• US 20080091714A1
• Filed: 03/08/2007
• Published: 04/17/2008
• Est. Priority Date: 10/16/2006
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Idicula, Sam, Chandrasekar, Sivasankaran, Agarwal, Nipun
• Granted Patent: US 7,933,935 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/83 Querying

Abstract

A method is provided to efficiently evaluate an expression to determine the partition key for an XML document stored in a database without the entire XML document first being stored in temporary memory storage. The partition key is determined using streaming evaluation or incrementally using a DOM node tree as a portion of the document is read and stored in the buffer. The XML document is stored in the partition using the read portion of the document stored in the buffer and the remaining portion from the original source.

Claims

1. A method, comprising:

reading into a buffer a portion of an XML document;

before reading into said buffer the entire XML document;

reading a certain portion of said XML document;

based on said certain portion of said XML document, determining that said XML document should be stored within a certain partition of a database table;

in response to determining that said XML document should be stored within a certain partition of a database table;

storing a portion of the XML document stored in the buffer in the partition; and

reading and storing a remainder of the XML document in the partition.

2. The method of claim 1, wherein determining that said XML document should be stored within a certain partition of a database table is performed by evaluating, based on said XML document, an expression that evaluates to a partition key value.

3. The method of claim 1, wherein determining that said XML document should be stored within a certain partition of a database table is performed by evaluating an expression containing an XPath expression.

4. The method of claim 2, wherein the expression to determine that said XML document should be stored within a certain partition of a database table is computed using streaming evaluation.

5. The method of claim 4, wherein said streaming evaluation ceases in response to a determination of the expression.

6. The method of claim 2, wherein the expression to determine that said XML document should be stored within a certain partition of a database table is computed using DOM evaluation.

7. The method of claim 6, wherein said DOM evaluation ceases in response to a determination of the expression.

8. The method, wherein the steps of claim 1 are performed by a database server.

12. A computer-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 1.

13. A computer-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 2.

14. A computer-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 3.

15. A computer-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 4.

16. A computer-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 5.

17. A computer-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 6.

18. A computer-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 7.

19. A computer-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 8.

9. A method, comprising:

a database system reading into a buffer a portion of an XML document;

before reading into said buffer the entire XML document;

said database system computing an expression based on partition key data in the portion of said XML document to generate a partition key value;

wherein said partition key value is associated with a partition of a partitioned database table;

said database system storing the portion of the XML document stored in the buffer in the partition; and

said database system reading and storing a remainder of the XML document in the partition.

10. The method of claim 9, wherein the expression to determine that said XML document should be stored within a certain partition of a database table is computed using streaming evaluation.

11. The method of claim 10, wherein said streaming evaluation ceases in response to a determination of the expression.

20. A computer-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 9.

21. A computer-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 10.

22. A computer-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 11.