Proactive space allocation in a database system

• US 20090030956A1
• Filed: 07/24/2007
• Published: 01/29/2009
• Est. Priority Date: 07/24/2007
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Mukherjee, Niloy, Ganesh, Amit, Muthulingam, Sujatha, Zhang, Wei
• Granted Patent: US 7,716,177 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 12/0223 User address space allocation, e.g. contiguous or non contiguous base addressing
• CPC Class Codes: G06F 16/284 Relational databases

Abstract

A method and apparatus for proactively allocating space to a logical layer of a database is provided. Allocation of space to a logical layer of a database is an expensive operation that should be minimized. The allocation of space includes discovering free space in all the higher layers in the logical storage hierarchy. It also includes cross-domain system calls and cleansing disk-write operations. In prior approaches, the allocation processes were triggered on-demand, only a certain logical layer was discovered to be at full capacity when an insert-row operation was attempted. In one embodiment of the invention, space needs are statistically predicted based on prior rates of space consumption. The database server pre-allocates space as needed, based on the statistical predictions. Rates of consumption are examined periodically. Space is pre-allocated before any logical layer reaches full capacity by a combination of proactive background processes; foreground-triggered, background processes; and classic foreground allocation.

Claims

1. A method comprising performing a machine-executed operation involving instructions, wherein said instructions are instructions that, when executed by one or more processors, cause the one or more processors to perform certain steps including:

determining a first quantity of space within a unit of logical structure that will be used within a particular period;

determining a second quantity of free space within the unit of logical structure;

comparing the first quantity and the second quantity;

based on the comparing, determining whether the second quantity is sufficient for the particular period;

if the second quantity is sufficient for the particular period, then performing the certain steps at a subsequent time; and

if the second quantity is not sufficient for the particular period, allocating space to the unit.

2. The method of claim 1, wherein the allocating further includes:

generating space allocation tasks based on the comparing step; and

executing the tasks.

3. The method of claim 1, wherein the determining a first quantity of space further includes:

collecting statistics of a particular unit of logical structure; and

analyzing the statistics.

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

5. The method of claim 1, wherein the steps are performed by a file storage server.

6. The method of claim 1, wherein the unit of logical structure is a tablespace.

7. The method of claim 1, wherein the unit of logical structure is a segment.

8. The method of claim 1, wherein the space is a datafile.

9. The method of claim 1, wherein the space is an extent.

10. The method of claim 1, wherein the space is a LOB chunk.

20. A computer-readable storage 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.

21. A computer-readable storage 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.

22. A computer-readable storage 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.

23. A computer-readable storage 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.

24. A computer-readable storage 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.

25. A computer-readable storage 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.

26. A computer-readable storage 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.

27. A computer-readable storage 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.

28. A computer-readable storage 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.

29. A computer-readable storage 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.

11. A method comprising performing a machine-executed operation involving instructions, wherein said instructions are instructions which, when executed by one or more processors, cause the one or more processors to perform certain steps including:

periodically determining a rate of consumption of space within a unit of logical storage structure;

based on the rate, determining a future time at which the unit will reach full capacity;

determining whether the future time is less than a threshold time; and

in response to determining that the future time is less than the threshold time, allocating space to the unit.

12. The method of claim 11, wherein the allocating further includes:

generating space allocation tasks; and

executing the tasks.

13. The method of claim 12, wherein the space allocation tasks are generated and executed by a system background if the threshold time is a first threshold.

14. The method of claim 12, wherein the space allocation tasks are generated and executed by a system foreground if the threshold time is a second threshold.

15. The method of claim 11, wherein the determining the future time occurs only if the rate of consumption is increasing.

16. The method of claim 11, wherein the rate of consumption includes a tablespace usage growth rate.

17. The method of claim 11, wherein the rate of consumption includes a segment usage growth rate.

18. The method of claim 11, wherein the allocating is in response to an alert that is generated in response to determining that the future time is less than the threshold time.

19. The method of claim 11, wherein the step of determining the rate of consumption is based on cumulative statistics.

30. A computer-readable storage 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.

31. A computer-readable storage 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 12.

32. A computer-readable storage 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 13.

33. A computer-readable storage 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 14.

34. A computer-readable storage 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 15.

35. A computer-readable storage 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 16.

36. A computer-readable storage 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 17.

37. A computer-readable storage 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 18.

38. A computer-readable storage 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 19.