Method and system for log management in a coupled data processing system

• US 5,737,600 A
• Filed: 04/15/1996
• Issued: 04/07/1998
• Est. Priority Date: 09/12/1994
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Warnes, James Henry, Zimmer, Dennis Jack, Phillips, Mark, Nick, Jeffrey Mark, Geiner, Robert Vaughn
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): LEWIS, CHERYL RENEA
• Application Number:
  US08/632,683
• Time in Patent Office: 722 Days
• Field of Search: 395/600, 395/616, 395/618, 395/617
• US Class Current: 1/1
• CPC Class Codes: G06F 16/23 Updating
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

In a coupled data processing system having multiple users, either in a single system or in a multi-system environment, a coupling facility storage structure is used to provide a log management facility. The log management facility provides for a real time physical log merge of the data written into the log stream without interprocessor communication required to process the records in logical sequence. The log management facility supports concurrent write, delete, browse, and asynchronous off-load to dasd processes across multi-users and multi-systems. The log management facility maintains the log records, independent of the log media, in time sequence. A logical block id is assigned to each log record written so that it can be directly accessed at a later time.

Claims

1. A method for managing log data in a data processing system comprising a plurality of processors, said method comprising:

writing, by said plurality of processors, a plurality of data records to a log stream, said log stream comprising at least a portion of a coupling facility storage structure residing within a coupling facility, said coupling facility sharable by said plurality of processors and comprising a processor and a communications facility, said writing comprising;

providing a real-time merge of said plurality of data records in a particular sequence, said providing comprising performing serialization for said log stream at said coupling facility, wherein said plurality of processors are relieved of providing said serialization for said log stream.

2. The method of claim 1, wherein said providing comprises writing said plurality of data records to said log stream in time sequence.

3. The method of claim 2, wherein said providing comprises:

determining a value for a list authority control; and

using said value to place said plurality of data records within said log stream in time sequence.

4. The method of claim 2, further comprising retrieving one or more of said plurality of data records using a selected time stamp.

5. The method of claim 1, further comprising determining a logical identifier for each of said plurality of data records, wherein each of said plurality of data records has a respective logical identifier, each logical identifier representing a logical offset into said log stream.

6. The method of claim 5, wherein each logical identifier represents a key for direct access to its respective data record when said respective data record resides in said at least a portion of said coupling facility storage structure.

7. The method of claim 5, wherein said log stream further comprises one or more data sets and wherein each logical identifier is usable in direct access of its respective data record when said respective data record resides in one of said one or more data sets.

8. The method of claim 1, wherein said at least a portion of said coupling facility storage structure comprises a list.

9. The method of claim 1, further comprising concurrently performing a function against said log stream being written to while maintaining integrity of said log stream.

10. The method of claim 9, wherein said function comprises one of the following functions:

a write function, a delete function, a read function and an off-load function.

11. The method of claim 1, wherein said log stream further comprises one or more data sets and said method further comprises off-loading one or more of said plurality of data records from said at least a portion of said coupling facility storage structure to said one or more data sets.

12. The method of claim 11, wherein said off-loading comprises:

reading one or more data records from said at least a portion of said coupling facility storage structure;

storing in an input/output buffer a predetermined amount of said one or more data records read from said at least a portion of said coupling facility storage structure; and

writing said input/output buffer to said one or more data sets when said predetermined amount of said one or more data records is stored in said input/output buffer.

13. The method of claim 12, further comprising repeating said storing and writing until said one or more data records read from said at least a portion of said coupling facility storage structure has been stored in said input/output buffer.

14. The method of claim 13, further comprising deleting from said at least a portion of said coupling facility storage structure said one or more data records read from said at least a portion of said coupling facility storage structure after said one or more data records is written to said one or more data sets.

15. The method of claim 11, further comprising off-loading said one or more data records until a predefined low threshold of resources has been attained for said at least a portion of said coupling facility storage structure.

16. A system for managing log data in a data processing system comprising a plurality of processors, said system comprising:

a log stream comprising at least a portion of a coupling facility storage structure residing within a coupling facility, said coupling facility sharable by said plurality of processors and comprising a processor and a communications facility, said coupling facility being adapted to provide serialization for said log stream, wherein said plurality of processors is relieved of providing said serialization for said log stream; and

means for writing, by said plurality of processors, a plurality of data records to said log stream in a particular sequence, wherein a real-time merge of said plurality of data records is provided.

17. The system of claim 16, wherein said means for writing comprises means for writing said plurality of data records to said log stream in time sequence.

18. The system of claim 17, wherein said means for writing comprises:

means for determining a value for a list authority control; and

means for using said value to place said plurality of data records within said log stream in time sequence.

19. The system of claim 17, further comprising means for retrieving one or more of said plurality of data records using a selected time stamp.

20. The system of claim 16, further comprising means for determining a logical identifier for each of said plurality of data records, wherein each of said plurality of data records has a respective logical identifier, each logical identifier representing a logical offset into said log stream.

21. The system of claim 20, wherein each logical identifier represents a key for direct access to its respective data record when said respective data record resides in said at least a portion of said coupling facility storage structure.

22. The system of claim 20, wherein said log stream further comprises one or more data sets and wherein each logical identifier is usable in direct access of its respective data record when said respective data record resides in one of said one or more data sets.

23. The system of claim 16, wherein said at least a portion of said coupling facility storage structure comprises a list.

24. The system of claim 16, further comprising means for concurrently performing a function against said log stream being written to while maintaining integrity of said log stream.

25. The system of claim 24, wherein said function comprises one of the following functions:

a write function, a delete function, a read function and an off-load function.

26. The system of claim 16, wherein said log stream further comprises one or more data sets and said system further comprises means for off-loading one or more of said plurality of data records from said at least a portion of said coupling facility storage structure to said one or more data sets.

27. The system of claim 26, wherein said means for off-loading comprises:

means for reading one or more data records from said at least a portion of said coupling facility storage structure;

an input/output buffer storing a predetermined amount of said one or more data records read from said at least a portion of said coupling facility storage structure; and

means for writing said input/output buffer to said one or more data sets when said predetermined amount of said one or more data records is stored in said input/output buffer.

28. The system of claim 27, further comprising means for deleting from said at least a portion of said coupling facility storage structure one or more data records read from said at least a portion of said coupling facility storage structure after said one or more data records is written to said one or more data sets.

29. The system of claim 26, further comprising means for off-loading said one or more data records until a predefined low threshold of resources has been attained for said at least a portion of said coupling facility storage structure.

30. A method for logging information in a data processing system comprising a first processor executing a first application and a second processor executing a second application, said method comprising:

said first application writing a first record to a log stream; and

said second application writing a second record to said log stream, said first and second applications writing independently of each other such that application serialization during said writing of said first record and said second record is not necessary, and wherein the writing of the first and second records provides a real-time merge of said first record and said second record in a predetermined logical sequence.

31. The method of claim 30, further comprising determining prior to writing said second record if said second record can be written to said log stream in said predetermined logical sequence.

32. The method of claim 31, wherein said predetermined logical sequence comprises ascending time order and wherein said determining comprises performing a list authority comparison, wherein said second record is not written when said list authority comparison is unsuccessful.

33. The method of claim 32, wherein said performing comprises:

comparing a comparative list authority operand with a list authority control to determine if a predefined relationship exists between said comparative list authority operand and said list authority control.

34. The method of claim 33, wherein said predefined relationship comprises a less than or equal operation.

35. The method of claim 30, further comprising assigning a first identifier to said first record and a second identifier to said second record, said first and second identifiers indicating the logical sequence of said first and second records in said log stream, said first identifier and said second identifier representing logical offsets into said log stream for direct access of said first record and said second record, respectively.

36. The method of claim 35, wherein said assigning is performed independently of other functions processing against said log stream.

37. The method of claim 35, further comprising using said first identifier during one or more operations requiring direct access to said first record.

38. The method of claim 37, wherein said one or more operations comprises one of deleting said first record from the log stream and reading said first record in the log stream.

39. The method of claim 35, wherein said log stream comprises at least a portion of a coupling facility storage structure and one or more data sets, and wherein said first identifier is usable in direct access of said first record regardless of its location in said at least a portion of said coupling facility storage structure and said one or more data sets.

40. The method of claim 30, wherein said first application and said second application each writes a plurality of records to said log stream in said predetermined logical sequence.

41. The method of claim 30, wherein said log stream comprises a portion of a coupling facility storage structure and one or more data sets and said method further comprises reading said log stream to read one of said first and second records regardless of its location in said at least a portion of said coupling facility storage structure and said one or more data sets.

42. The method of claim 30, further comprising:

assigning, by said first processor, a first identifier to said first record as part of said writing of said first record; and

assigning, by said second processor, a second identifier to said second record as part of said writing of said second record, wherein said first processor assigns said first identifier and said second processor assigns said second identifier without communicating with each other about the assigning of the first and second identifiers.

43. The method of claim 42, wherein said assigning said first identifier comprises setting said first identifier equal to an assignment variable.

44. The method of claim 43, further comprising:

determining an increment value; and

updating said assignment variable by said increment value, wherein the updated assignment variable comprises said second identifier.

45. The method of claim 30, wherein said log stream comprises a coupling facility list structure and one or more data sets.

46. A method for assigning identifiers to data records within a data processing system, said method comprising:

dynamically determining a unique identifier for a record to be written to a stream of records, said identifier being in logical sequence with any other identifiers associated with said stream of records and representing a logical relative offset into said stream of records for direct access of said record, wherein said identifier is determined independently of other functions being processed against said stream of records; and

assigning said identifier to said record when said record is written to said stream of records.

47. The method of claim 46, wherein said other functions comprises one of a write function, a delete function, a read function and an off-load function.

48. The method of claim 46, wherein said stream of records comprises at least a portion of a coupling facility storage structure and a data set, and wherein said identifier is usable in direct access of said record, regardless of whether said record is stored in said coupling facility storage structure or said data set.

49. The method of claim 46, wherein said assigning comprises setting said identifier equal to an assignment variable.

50. The method of claim 49, further comprising:

determining an increment value; and

updating said assignment variable by said increment value, wherein the updated assignment variable comprises a next identifier to be assigned.

51. A system for logging information in a data processing system, said system comprising:

a first processor adaptable to write a first record to a log stream; and

a second processor adaptable to write a second record to said log stream, said first and second processors being adaptable to write independently of each other such that application serialization during said writing of said first record and said second record is not necessary, and wherein the writing of the first and second records provides a real-time merge of said first record and said second record in a predetermined logical sequence.

52. The system of claim 51, further comprising means for determining prior to writing said second record if said second record can be written to said log stream in said predetermined logical sequence.

53. The system of claim 52, wherein said predetermined logical sequence comprises ascending time order and wherein said means for determining comprises means for performing a list authority comparison, wherein said second record is not written when said list authority comparison is unsuccessful.

54. The system of claim 53, wherein said means for performing comprises:

means for comparing a comparative list authority operand with a list authority control to determine if a predefined relationship exists between said comparative list authority operand and said list authority control.

55. The system of claim 54, wherein said predefined relationship comprises a less than or equal operation.

56. The system of claim 51, further comprising means for assigning a first identifier to said first record and a second identifier to said second record, said first and second identifiers indicating the logical sequence of said first and second records in said log stream, said first identifier and said second identifier representing logical offsets into said log stream for direct access of said first record and said second record, respectively.

57. The system of claim 56, wherein said means for assigning is performed independently of other functions processing against said log stream.

58. The system of claim 56, further comprising means for using said first identifier during one or more operations requiring direct access to said first record.

59. The system of claim 58, wherein said one or more operations comprises one of deleting said first record from the log stream and reading said first record in the log stream.

60. The system of claim 56, wherein said log stream comprises at least a portion of a coupling facility storage structure and one or more data sets, and wherein said first identifier is usable in direct access of said first record regardless of its location in said at least a portion of said coupling facility storage structure and said one or more data sets.

61. The system of claim 51, wherein said first application and said second application each writes a plurality of records to said log stream in said predetermined logical sequence.

62. The system of claim 51, wherein said log stream comprises a portion of a coupling facility storage structure and one or more data sets and said system further comprises means for reading said log stream to read one of said first and second records regardless of its location in said at least a portion of said coupling facility storage structure and said one or more data sets.

63. The system of claim 51, wherein:

said first processor is adaptable to assign a first identifier to said first record as part of said writing of said first record; and

said second processor is adaptable to assign a second identifier to said second record as part of said writing of said second record, and wherein said first processor assigns said first identifier and said second processor assigns said second identifier without communicating with each other about the assigning of the first and second identifiers.

64. The system of claim 63, wherein said assigning said first identifier comprises means for setting said first identifier equal to an assignment variable.

65. The system of claim 64, further comprising:

means for determining an increment value; and

means for updating said assignment variable by said increment value, wherein the updated assignment variable comprises said second identifier.

66. The system of claim 51, wherein said log stream comprises a coupling facility list structure and one or more data sets.

67. A system for assigning identifiers to data records within a data processing system, said system comprising:

means for dynamically determining a unique identifier for a record to be written to a stream of records, said identifier being in logical sequence with any other identifiers associated with said stream of records and representing a logical relative offset into said stream of records for direct access of said record, wherein said identifier is determined independently of other functions being processed against said stream of records; and

means for assigning said identifier to said record when said record is written to said stream of records.

68. The system of claim 67, wherein said other functions comprises one of a write function, a delete function, a read function and an off-load function.

69. The system of claim 67, wherein said stream of records comprises at least a portion of a coupling facility storage structure and a data set, and wherein said identifier is usable in direct access of said record, regardless of whether said record is stored in said coupling facility storage structure or said data set.

70. The system of claim 67, wherein said means for assigning comprises means for setting said identifier equal to an assignment variable.

71. The system of claim 70, further comprising:

means for determining an increment value; and

means for updating said assignment variable by said increment value, wherein the updated assignment variable comprises a next identifier to be assigned.