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

• US 10,394,452 B2
• Filed: 06/05/2017
• Issued: 08/27/2019
• Est. Priority Date: 09/14/2012
• Status: Active Grant

• 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:
  US15/614,495
• Publication Number:
  US 20170269848A1
• Time in Patent Office: 813 Days
• 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;

providing a duration parameter indicating an amount of time after which unused pages are eligible for reuse; and

selecting for reuse at least one page allocated to at least one of the leaf nodes and the internal nodes that has not been used for the duration parameter, wherein the internal nodes are selected for reuse after determining not to select one of the leaf nodes for reuse when the leaf nodes been used within the duration parameter.

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 duration parameter includes a leaf node duration and an internal node duration, wherein the leaf node duration is used to select one of the leaf nodes for reuse and wherein the internal node duration is used to select one of the internal nodes for use.

4. The computer program product of claim 3, wherein the leaf node duration is less than the internal node duration to cause pages implementing leaf nodes to be selected for reuse at a higher rate than pages implementing internal nodes.

5. The computer program product of claim 1, wherein the internal and leaf node durations are expressed as a number of memory clock cycles.

6. The computer program product of claim 1, wherein the amount of time of the duration parameter comprises a number of clock cycles.

7. 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;

providing a duration parameter indicating an amount of time after which unused pages are eligible for reuse; and

selecting for reuse at least one selected page allocated to at least one of the leaf nodes and the internal nodes that has not been used for the duration parameter, wherein the internal nodes are selected for reuse after determining not to select one of the leaf nodes for reuse when the leaf nodes been used within the duration parameter.

8. The system of claim 7, 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.

9. The system of claim 7, wherein the duration parameter includes a leaf node duration and an internal node duration, wherein the leaf node duration is used to select one of the leaf nodes for reuse and wherein the internal node duration is used to select one of the internal nodes for use.

10. The system of claim 9, wherein the leaf node duration is less than the internal node duration to cause pages implementing leaf nodes to be selected for reuse at a higher rate than pages implementing internal nodes.

11. The system of claim 7, wherein the internal and leaf node durations are expressed as a number of memory clock cycles.

12. The system of claim 7, wherein the amount of time of the duration parameter comprises a number of clock cycles.

13. 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;

providing a duration parameter indicating an amount of time after which unused pages are eligible for reuse; 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 duration parameter for reuse, wherein the internal nodes are selected for reuse after determining not to select one of the leaf nodes for reuse when the leaf nodes been used within the duration parameter.

14. The method of claim 13, 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.

15. The method of claim 13, wherein the duration parameter includes a leaf node duration and an internal node duration, wherein the leaf node duration is used to select one of the leaf nodes for reuse and wherein the internal node duration is used to select one of the internal nodes for use.

16. The method of claim 15, wherein the leaf node duration is less than the internal node duration to cause pages implementing leaf nodes to be selected for reuse at a higher rate than pages implementing internal nodes.

17. The method of claim 15, A method, 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;

providing a leaf node duration indicating an amount of time after which an unused page at one of the leaf nodes is selected for reuse and an internal node duration after which an unused page at an internal node is selected for reuse; and

selecting at least one selected page for reuse allocated to at least one of the leaf nodes and the internal nodes periodically at a reuse selection interval, wherein the reuse selection interval is set so that pages implementing the internal and leaf nodes have been unused for a duration that exceeds the internal node duration and the leaf node duration, respectively, after each instance of the reuse selection interval resulting in performing the selecting the at least one selected page.

18. The method of claim 13, wherein the internal and leaf node durations are expressed as a number of memory clock cycles.

19. The method of claim 13, wherein the amount of time of the duration parameter comprises a number of clock cycles.

20. 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;

providing a leaf node duration indicating an amount of time after which an unused page at one of the leaf nodes is selected for reuse and an internal node duration after which an unused page at an internal node is selected for reuse; and

selecting at least one page for reuse allocated to at least one of the leaf nodes and the internal nodes periodically at a reuse selection interval, wherein the reuse selection interval is set so that pages implementing the internal and leaf nodes have been unused for a duration that exceeds the internal node duration and the leaf node duration, respectively, after each instance of the reuse selection interval resulting in the selecting the at least one page.

21. 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;

providing a leaf node duration indicating an amount of time after which an unused page at one of the leaf nodes is selected for reuse and an internal node duration after which an unused page at an internal node is selected for reuse; and

selecting for reuse at least one page for reuse allocated to at least one of the leaf nodes and the internal nodes periodically at a reuse selection interval, wherein the reuse selection interval is set so that pages implementing the internal and leaf nodes have been unused for a duration that exceeds the internal node duration and the leaf node duration, respectively, after each instance of the reuse selection interval resulting in the selecting the at least one page.