Method and apparatus for logging journal data using a log write ahead data set
US4507751A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 21, 1982 |
| Grant date | Mar 26, 1985 |
| Priority date | — |
| Expiry date | Jun 21, 2002 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99953
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The invention provides a computing apparatus and method for maintaining a journal log. The computing apparatus includes volatile storage for storing a log buffer and a non-volatile storage for storing a journal log. Non-volatile storage means are provided for storing in a write-ahead data set a plurality of short data blocks. The log buffer contents are written to the write-ahead data set responsive to a process epoch occurring before the log buffer is filled. The log buffer contents are written to the journal log upon the log buffer being filled. The redoing or undoing of data base changes is made with reference to the write ahead data set only in the case of a system failure resulting in loss of log buffer data not yet written to the journal log; otherwise data base changes are redone or undone with reference to the log buffer or journal log.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.