Strategies for pushing out database blocks from cache
US9244980B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 12, 2013 |
| Grant date | Jan 26, 2016 |
| Priority date | — |
| Expiry date | Jan 25, 2034 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F12/0862
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Data of a columnar database is organized into extents. Each extent occupies contiguous storage on the disk. An extent stores database blocks of a column of a database table. The database system adds new database blocks of a column to the extents assigned to that column. When a request for adding a block to a table is received, the extent for the table and column combination is obtained and the block added to the extent. Prefetching strategies are used to retrieve database blocks in advance of an actual request. The rate of prefetching is determined per column. The rate of prefetching is adjusted based on the number of faults encountered for the column. Database blocks no longer needed in memory are pushed out. When a scan process is reading blocks, as soon as the block has been processed it is scheduled to be pushed out.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.