Selecting pages implementing leaf nodes and internal nodes of a data set index for reuse

• US 9,378,305 B1
• Filed: 02/19/2016
• Issued: 06/28/2016
• Est. Priority Date: 09/14/2012
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Erdmann, Derek L., Reed, David C., Reed, Thomas C., Smith, Max D.
• Primary Examiner(s): CARDWELL, ERIC
• Application Number:
  US15/048,683
• Publication Number:
  US 20160170654A1
• Time in Patent Office: 130 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 12/023 Free address space management
• CPC Class Codes: G06F 12/1009 using page tables, e.g. page table structures
• CPC Class Codes: G06F 16/2246 Trees, e.g. B+trees
• CPC Class Codes: G06F 16/9027 Trees
• CPC Class Codes: G06F 2212/152 Virtualized environment, e.g. logically partitioned system
• CPC Class Codes: G06F 2212/657 Virtual address space management
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/0631 by allocating resources to storage systems
• CPC Class Codes: G06F 3/0644 Management of space entities, e.g. partitions, extents, pools
• CPC Class Codes: G06F 3/0665 at area level, e.g. provisioning of virtual or logical volumes
• CPC Class Codes: G06F 3/0673 Single storage device

Abstract

Provided are a computer program product, system, and method for selecting pages implementing leaf nodes and internal nodes of a data set index for reuse in memory. Pages in the memory are allocated to internal nodes and leaf nodes of a tree data structure representing all or a portion of a data set index for the data set. At least at least one duration parameter indicates an amount of time after which an unused page implement one of the internal nodes or leaf nodes is eligible for reuse. Selection is made of at least one selected page allocated to at least one of the leaf nodes and the internal nodes that has not been used for one of the at least one duration parameter for reuse.

Claims

1. A computer program product for managing a data set stored in a storage in a memory, the computer program product comprising a non-transitory computer readable storage medium having computer readable program code embodied therein that executes to perform operations, the operations comprising:

allocating pages in the memory to internal nodes and leaf nodes of a tree data structure representing all or a portion of a data set index for the data set;

maintaining a leaf node duration and an internal node duration, wherein the leaf node duration indicates an amount of time after which an unused page allocated to one of the leaf nodes is eligible for reuse and wherein the internal node duration indicates an amount of time after which an unused page allocated to one of the internal nodes is eligible for reuse, wherein the internal node duration comprises a greater temporal duration than the leaf node duration to cause the leaf nodes to be selected at a higher rate for reuse than the internal nodes; and

selecting at least one selected page allocated to at least one of the leaf nodes and the internal nodes that has not been used for one of the at least one of the leaf node duration and the internal node duration, respectively, for reuse.

2. The computer program product of claim 1, wherein the leaf nodes include information on members of the data set, wherein the internal nodes include one or more keys used to traverse the tree data structure to reach the leaf nodes that are used to access the members of the data set.

3. The computer program product of claim 1, wherein the operations further comprise:

determining whether a utilization rate indicating an amount of the pages that are not available for reuse to be allocated to leaf nodes and internal nodes exceeds a threshold; and

decreasing at least one of the leaf node duration and the internal node duration in response to determining that the utilization rate exceeds the threshold.

4. The computer program product of claim 3, wherein the operations further comprise:

increasing at least one of the leaf node duration and the internal node duration in response to determining that the utilization rate does not exceed the threshold.

5. The computer program product of claim 3, wherein the utilization rate is based on a number of the pages allocated to the leaf nodes and the internal nodes not indicated as available for reuse and a total number of pages allocated.

6. A system for managing a data set stored in a storage, comprising:

a processor;

a memory;

a computer readable storage medium having code executed by the processor to perform operations, the operations comprising;

allocating pages in the memory to internal nodes and leaf nodes of a tree data structure representing all or a portion of a data set index for the data set;

maintaining a leaf node duration and an internal node duration, wherein the leaf node duration indicates an amount of time after which an unused page allocated to one of the leaf nodes is eligible for reuse and wherein the internal node duration indicates an amount of time after which an unused page allocated to one of the internal nodes is eligible for reuse, wherein the internal node duration comprises a greater temporal duration than the leaf node duration to cause the leaf nodes to be selected at a higher rate for reuse than the internal nodes; and

selecting at least one selected page allocated to at least one of the leaf nodes and the internal nodes that has not been used for one of the at least one of the leaf node duration and the internal node duration, respectively, for reuse.

7. The system of claim 6, wherein the leaf nodes include information on members of the data set, wherein the internal nodes include one or more keys used to traverse the tree data structure to reach the leaf nodes that are used to access the members of the data set.

8. The system of claim 6, wherein the operations further comprise:

determining whether a utilization rate indicating an amount of the pages that are not available for reuse to be allocated to leaf nodes and internal nodes exceeds a threshold; and

decreasing at least one of the leaf node duration and the internal node duration in response to determining that the utilization rate exceeds the threshold.

9. The system of claim 8, wherein the operations further comprise:

increasing at least one of the leaf node duration and the internal node duration in response to determining that the utilization rate does not exceed the threshold.

10. The system of claim 8, wherein the utilization rate is based on a number of the pages allocated to the leaf nodes and the internal nodes not indicated as available for reuse and a total number of pages allocated.

11. A method, comprising:

allocating pages in a memory to internal nodes and leaf nodes of a tree data structure in a non-transitory computer readable storage medium representing all or a portion of a data set index for a data set;

maintaining a leaf node duration and an internal node duration, wherein the leaf node duration indicates an amount of time after which an unused page allocated to one of the leaf nodes is eligible for reuse and wherein the internal node duration indicates an amount of time after which an unused page allocated to one of the internal nodes is eligible for reuse, wherein the internal node duration comprises a greater temporal duration than the leaf node duration to cause the leaf nodes to be selected at a higher rate for reuse than the internal nodes; and

selecting at least one selected page allocated to at least one of the leaf nodes and the internal nodes that has not been used for one of the at least one of the leaf node duration and the internal node duration, respectively, for reuse.

12. The method of claim 11, wherein the leaf nodes include information on members of the data set, wherein the internal nodes include one or more keys used to traverse the tree data structure to reach the leaf nodes that are used to access the members of the data set.

13. The method of claim 11, further comprising:

determining whether a utilization rate indicating an amount of the pages that are not available for reuse to be allocated to leaf nodes and internal nodes exceeds a threshold; and

decreasing at least one of the leaf node duration and the internal node duration in response to determining that the utilization rate exceeds the threshold.

14. The method of claim 13, further comprising:

increasing at least one of the leaf node duration and the internal node duration in response to determining that the utilization rate does not exceed the threshold.

15. The method of claim 13, wherein the utilization rate is based on a number of the pages allocated to the leaf nodes and the internal nodes not indicated as available for reuse and a total number of pages allocated.