Techniques for managing XML data associated with multiple execution units

• US 8,949,220 B2
• Filed: 03/26/2004
• Issued: 02/03/2015
• Est. Priority Date: 12/19/2003
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Liu, Zhen, Krishnaprasad, Muralidhar, Manikutty, Anand, Murthy, Ravi, Warner, James, Chang, Thomas H., Arora, Vikas, Kotsovolos, Susan
• Primary Examiner(s): Alam, Hosain
• Assistant Examiner(s): Ahluwalia, Navneet K
• Application Number:
  US10/810,152
• Publication Number:
  US 20050138047A1
• Time in Patent Office: 3,966 Days
• Field of Search: 707 1- 10, 707100-1041, 707200-205, 707/718, 707/804, 707/719
• US Class Current: 707/718
• CPC Class Codes: G06F 16/88 Mark-up to mark-up conversion conversion for visualization in web browsing G06F16/9577

Abstract

Techniques for managing XML data associated with multiple execution units ensure that execution units are able to use XML data coming from other execution units. Such techniques are applicable when, but for the technique, an XML type value is produced in a particular form by one execution unit and is supposed to be consumed by another execution unit that is unable to process data in the particular form, and involves detecting that the foregoing situation exists and annotating information sent to an XML producer execution unit to cause the XML type value to be transformed into a canonical form that can be shared by all relevant execution units.

Claims

1. A method comprising:

analyzing a query execution plan that specifies tasks to be performed by a plurality of execution units;

wherein the plurality of execution units include a first execution unit and a second execution unit;

wherein the query execution plan is to service a request for data;

wherein analyzing the query execution plan includes;

detecting that a portion of the query execution plan specifies first tasks to be performed by the first execution unit;

detecting that another portion of the query execution plan specifies second tasks to be performed by the second execution unit; and

detecting that, as a result of performing the first tasks, the first execution unit will generate XML data that the second execution unit needs to perform the second tasks;

generating information to send to said first execution unit to cause said first execution unit to perform said first tasks;

wherein, in the absence of any annotation, said information would cause said first execution unit to generate the XML data in a first form that cannot be used by said second execution unit;

wherein, in said first form, the XML data generated by the first execution unit includes one or more references to execution unit-specific data that is accessible by the first execution unit but that is not accessible by the second execution unit; and

annotating said information with an annotation that causes the XML data generated by said first execution unit in the first form to be transformed to a second form for use by said second execution unit in performing said second tasks;

wherein, in said second form, the XML data does not include any references to execution unit-specific data; and

wherein the method is performed by one or more computing devices.

2. The method of claim 1, wherein the step of generating information includes generating information that, prior to annotating said information, would cause said first execution unit to generate the XML data in said first form that cannot be used by said second execution unit, and wherein said second form is different from said first form.

3. The method of claim 2, wherein said first form includes information to locate data that is stored in memory that is exclusive to said first execution unit, and wherein said information to locate data stored in said memory cannot be used by said second execution unit.

4. The method of claim 1, wherein said request for data is a database query and said query execution plan is a query plan.

5. The method of claim 4, wherein said information is one or more database commands.

6. The method of claim 1, wherein said annotation specifies a transformation operator.

7. The method of claim 6, further comprising:

executing said transformation operator, by said first execution unit, to transform the XML data generated by said first execution unit to said second form; and

sending the XML data that is transformed by said first execution unit to said second execution unit in said second form.

8. The method of claim 6, wherein said annotation specifies arguments for said transformation operator, to specify said second form.

9. The method of claim 1, further comprising:

transforming, by said first execution unit, the XML data to said second form based on said annotation.

10. The method of claim 1, wherein the step of annotating includes annotating said information with an operator to transform the XML data to said second form in which the XML data is serialized to represent particular data for a particular XML construct and is included in a serialized image that is sent to said second execution unit.

11. The method of claim 1, wherein the step of annotating includes annotating said information with an operator to transform the XML data to said second form which includes an identifier of memory space where the XML data is persistently stored, and wherein the XML data in said memory space is accessible by said second execution unit.

12. The method of claim 1, wherein the step of annotating includes annotating said information with an operator to transform the XML data to said second form in which the XML data is compressed according to a particular compression form that said second execution unit is able to decompress.

13. The method of claim 1, wherein said first execution unit and said second execution unit are different execution units that are executing, in parallel, work associated with servicing said request.

14. The method of claim 1, wherein said first execution unit and said second execution unit are different execution units that are each executing, on different servers of a distributed database system, work associated with servicing said request.

15. The method of claim 1, wherein the steps of detecting, generating and annotating are performed by a means that distributes work associated with servicing said request to said first execution unit and said second execution unit, and wherein said first execution unit and said second execution unit are different execution units that are each executing said work associated with servicing said request.

16. The method of claim 15, wherein said first execution unit and said second execution unit are each executing, on different data sources, said work associated with servicing said request.

17. The method of claim 15, wherein said means that distributes said work comprises an application server.

18. The method of claim 15, wherein said means that distributes said work comprises an application that manages workload among multiple means for executing said work.

19. The method of claim 1, further comprising:

determining said second form from information that describes preferences of each of multiple execution units that performs work associated with servicing said request.

20. A non-transitory computer-readable storage medium storing one or more sequences of instructions which, when executed by one or more processors, cause performance of steps comprising:

analyzing a query execution plan that specifies tasks to be performed by a plurality of execution units;

wherein the plurality of execution units include a first execution unit and a second execution unit;

wherein the query execution plan is to service a request for data;

wherein analyzing the query execution plan includes;

detecting that a portion of the query execution plan specifies first tasks to be performed by the first execution unit;

detecting that another portion of the query execution plan specifies second tasks to be performed by the second execution unit; and

detecting that, as a result of performing the first tasks, the first execution unit will generate XML data the second execution unit needs to perform the second tasks;

generating information to send to said first execution unit to cause said first execution unit to perform first tasks;

wherein in the absence of any annotation, said information would cause said first execution unit to generate the XML data in a first form that cannot be used by said second execution unit;

wherein, in said first form, the XML data includes one or more references to execution unit-specific data that is accessible by the first execution unit but that is not accessible by the second execution unit; and

annotating said information with an annotation that causes the XML data generated by said first execution unit to be transformed to a second form for use by said second execution unit in performing said second tasks;

wherein, in said second form, the XML data does not include any references to execution unit-specific data.

21. The non-transitory computer-readable storage medium of claim 20,

wherein the instructions that cause generating information further comprise additional instructions which, when executed, cause performance of steps comprising:

generating information that, prior to annotating said information, would cause said first execution unit to generate the XML data in said first form that cannot be used by said second execution unit; and

wherein said second form is different from said first form.

22. The non-transitory computer-readable storage medium of claim 21,

wherein said first form includes information to locate data that is stored in memory that is exclusive to said first execution unit, and wherein said information to locate data stored in said memory cannot be used by said second execution unit.

23. The non-transitory computer-readable storage medium of claim 20, wherein said request for data is a database query and said query execution plan is a query plan.

24. The non-transitory computer-readable storage medium of claim 20, wherein said information is one or more database commands.

25. The non-transitory computer-readable storage medium of claim 20, wherein said annotation specifies a transformation operator.

26. The non-transitory computer-readable storage medium of claim 25, further storing additional instructions which, when executed, cause performance of steps comprising:

executing said transformation operator, by said first execution unit, to transform the XML data generated by said first execution unit to said second form; and

sending the XML data that is transformed by said first execution unit to said second execution unit in said second form.

27. The non-transitory computer-readable storage medium of claim 25, wherein said annotation specifies arguments for said transformation operator, to specify said second form.

28. The non-transitory computer-readable storage medium of claim 20, further storing additional instructions which, when executed, cause performance of steps comprising:

transforming, by said first execution unit, the XML data to said second form based on said annotation.

29. The non-transitory computer-readable storage medium of claim 20, wherein the instructions that cause annotating further comprise additional instructions which, when executed, cause performance of steps comprising:

annotating said information with an operator to transform the XML data to said second form in which the XML data is serialized to represent particular data for a particular XML construct and is included in a serialized image that is sent to said second execution unit.

30. The non-transitory computer-readable storage medium of claim 20, wherein the instructions that cause annotating further comprise additional instructions which, when executed, cause performance of steps comprising:

annotating said information with an operator to transform the XML data to said second form which includes an identifier of memory space where the XML data is persistently stored, and wherein the XML data in said memory space is accessible by said second execution unit.

31. The non-transitory computer-readable storage medium of claim 20, wherein the instructions that cause annotating further comprise additional instructions which, when executed, cause performance of steps comprising:

annotating said information with an operator to transform the XML data to said second form in which the XML data is compressed according to a particular compression form that said second execution unit is able to decompress.

32. The non-transitory computer-readable storage medium of claim 20, wherein said first execution unit and said second execution unit are different execution units that are executing, in parallel, work associated with servicing said request.

33. The non-transitory computer-readable storage medium of claim 20, wherein said first execution unit and said second execution unit are different execution units that are each executing, on different servers of a distributed database system, work associated with servicing said request.

34. The non-transitory computer-readable storage medium of claim 20, wherein the instructions that cause detecting, generating and annotating are performed by a means that distributes work associated with servicing said request to said first execution unit and said second execution unit, and wherein said first execution unit and said second execution unit are different execution units that are each executing said work associated with servicing said request.

35. The non-transitory computer-readable storage medium of claim 34, wherein said first execution unit and said second execution unit are each executing, on different data sources, said work associated with servicing said request.

36. The non-transitory computer-readable storage medium of claim 34, wherein said means that distributes said work comprises an application server.

37. The non-transitory computer-readable storage medium of claim 34, wherein said means that distributes said work comprises an application that manages workload among multiple means for executing said work.

38. The non-transitory computer-readable storage medium of claim 20, further storing additional instructions which, when executed, cause performance of steps comprising:

determining said second form from information that describes preferences of each of multiple execution units that performs work associated with servicing said request.

39. A method for processing XML data, comprising:

analyzing a query execution plan that specifies tasks to be performed by a plurality of execution units;

wherein the plurality of execution units include a first execution unit and a second execution unit;

wherein the query execution plan is to service a request for data;

wherein analyzing the query execution plan includes;

receiving information at the first execution unit to cause said first execution unit to perform first tasks;

detecting that another portion of the query execution plan specifies second tasks to be performed by the second execution unit; and

detecting that, as a result of performing the first tasks, the first execution unit will generate XML data that the second execution unit needs to perform the second tasks;

wherein, in the absence of any annotation, said information would cause said first execution unit to generate the XML data in a first form that cannot be used by said second execution unit;

wherein, in said first form, the XML data includes one or more references to execution unit-specific data that is accessible by the first execution unit but that is not accessible by the second execution unit;

annotating said information with an annotation that causes the XML data generated by said first execution unit to be transformed to a second form for use by said second execution unit in performing said second tasks;

wherein, in said second form, the XML data does not include any references to execution unit-specific data; and

providing XML data that is annotated to said second execution unit in said second form for use in performing said second tasks by said second execution unit;

wherein the method is performed by one or more computing devices.

40. The method of claim 39, wherein the step of transforming the XML data to said second form is performed by said first execution unit.

41. The method of claim 40, wherein the step of transforming comprises executing an operator specified in said annotation.

42. A non-transitory computer-readable storage medium storing one or more sequences of instructions which, when executed by one or more processors, cause performance of steps comprising:

analyzing a query execution plan that specifies tasks to be performed by a plurality of execution units;

wherein the plurality of execution units include a first execution unit and a second execution unit;

wherein the query execution plan is to service a request for data;

wherein analyzing the query execution plan includes;

receiving information at the first execution unit to cause said first execution unit to perform first tasks;

detecting that another portion of the query execution plan specifies second tasks to be performed by the second execution unit; and

detecting that, as a result of performing the first tasks, the first execution unit will generate XML data that the second execution unit needs to perform the second tasks;

wherein in the absence of any annotation, said information would cause said first execution unit to generate the XML data in a first form that cannot be used by said second execution unit;

wherein, in said first form, the XML data includes one or more references to execution unit-specific data that is accessible by the first execution unit but that is not accessible by the second execution unit;

annotating said information with an annotation that causes the XML data generated by said first execution unit to be transformed to a second form for use by said second execution unit in performing said second task;

wherein, in said second form, the XML data does not include any references to execution unit-specific data; and

providing XML data that is annotated to said second execution unit in said second form for use in performing said second tasks by said second execution unit.

43. The non-transitory computer-readable storage medium of claim 42, wherein the instructions that cause transforming the XML data to said second form are performed by said first execution unit.

44. The non-transitory computer-readable storage medium of claim 43, wherein the instructions that cause transforming further comprise additional instructions which, when executed, cause performance of steps comprising:

executing an operator specified in said annotation.