发明授权
- 专利标题: Performing index scans in a database
- 专利标题(中): 在数据库中执行索引扫描
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申请号: US13224623申请日: 2011-09-02
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公开(公告)号: US09087087B2公开(公告)日: 2015-07-21
- 发明人: Robert W. Lyle , Ping Wang
- 申请人: Robert W. Lyle , Ping Wang
- 申请人地址: US NY Armonk
- 专利权人: International Business Machines Corporation
- 当前专利权人: International Business Machines Corporation
- 当前专利权人地址: US NY Armonk
- 代理机构: Mollborn Patents, Inc.
- 代理商 Fredrik Mollborn
- 主分类号: G06F17/30
- IPC分类号: G06F17/30
摘要:
Methods and apparatus, including computer program products, implementing and using techniques for performing an index scan in a database system. A sequence of pages visited during an index scan are dynamically tracked. The tracking includes tracking the number of page accesses requiring a wait for input or output. It is determined whether prefetching of an object is desirable. The determination being made at least in part based on the number of page accesses requiring a wait for input or output. If prefetching is desirable, a prefetching method is selected among a set of available prefetching methods. An effectiveness of the selected prefetching method is continuously monitored by tracking the sequence of pages accessed and available access methods. A different prefetching method is selected from the set of available prefetching methods if the different prefetching method has a better effectiveness for a portion of the index that is being scanned.
公开/授权文献
- US20130060781A1 PERFORMING INDEX SCANS IN A DATABASE 公开/授权日:2013-03-07