Consistent data storage in an object cache
US6128627A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 15, 1998 |
| Grant date | Oct 3, 2000 |
| Priority date | — |
| Expiry date | Apr 15, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99953
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method for consistently storing cached objects in the presence of failures is provided. This method ensures atomic object consistency--in the event of failure and restart, an object will either be completely present or completely absent from the cache, never truncated or corrupted. Furthermore, this consistency comes without any time-consuming data structure reconstruction on restart. In this scheme, objects are indexed by a directory table that is stored in main memory and mapped to non-volatile storage, and changes to the directory table are buffered into an open directory that is stored in main memory. Cache objects are either stored in volatile aggregation buffers or in segments of non-volatile disk storage called arenas. Objects are first coalesced into memory-based aggregation buffers, and later committed to disk. Locking is used to control parallel storage to aggregation buffers. Directory entries pointing to objects are only permitted to be written to persistent disk storage after the target objects are themselves committed to disk, preventing dangling pointers. Periodically, when the contents of open directory entries point to objects that are stably stored on disk, the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.