Abstract
A database system can generally be divided into three major components. One component supports the logical database as seen by the user. Another component maps the information into physical records. The third component, called the storage component, is responsible for mapping these records onto auxiliary storage (generally disks) and controlling their transfer to and from main storage.
This paper is primarily concerned with the implementation of a storage component. It considers a simple and classical interface to the storage component: Seen at this level the database is a collection of segments. Each segment is a linear address space.
A recovery scheme is first proposed for system failure (hardware or software error which causes the contents of main storage to be lost). It is based on maintaining a dual mapping between pages and their location on disk. One mapping represents the current state of a segment being modified; the other represents a previous backup state. At any time the backup state can be replaced by the current state without any data merging. Procedures for segment modification, save, and restore are analyzed. Another section proposes a facility for protection against damage to the auxiliary storage itself. It is shown how such protection can be obtained by copying on a tape (checkpoint) only those pages that have been modified since the last checkpoint.
- 1 ASTRAHAN, M.M., ET AL. System R: Relational approach to data base management. A C'M Trans. Database Eyst. 1, 2 (June 1976), 97-137. Google ScholarDigital Library
- 2 IBM CORP. OS/VS Data Management Services Guide. Ref. Man. GC26-3783, IBM Corp., White Plains, N.Y., 1975.Google Scholar
- 3 LORIE, R.A., AND SYMOSDS, A.J. A relational access method for interactive applications. In Courant Comptr. Sci. Syrup., Vol. 6, Data Base Systems, Prentice-Hall, Englewood Cliffs, N.J., 1971, pp. 99-124.Google Scholar
- 4 LORIE, R.A. XRM: An extended (N-ary) relational memory. Tech. Rep. 320-2096, IBM Scientific Ctr., Cambridge, Mass., Jan. 1974.Google Scholar
- 5 SEVERANCe, D.G., A~D LOHM~N, G.M. ~ifferential files: their application to the maintenance of large databases. ACM Trans. Database ,Syst. 1, 3 (Sept. 1976), 256-267. Google ScholarDigital Library
Index Terms
- Physical integrity in a large segmented database
Recommendations
A recovery method of deleted record for SQLite database
SQLite is a small-sized database engine largely used in embedded devices and local application software. The availability of portable devices, such as smartphones, has been extended over the recent years and has contributed to growing adaptation of ...
Disk Read-Write Optimizations and Data Integrity in Transaction Systems Using Write-Ahead Logging
ICDE '95: Proceedings of the Eleventh International Conference on Data EngineeringWe discuss several disk read-write optimizations that are implemented in different transaction systems and disk hardware to improve performance. These include: (1) when multiple sectors are written to disk, the sectors may be written out of sequence (...
CRFS: A Lightweight User-Level Filesystem for Generic Checkpoint/Restart
ICPP '11: Proceedings of the 2011 International Conference on Parallel ProcessingCheckpoint/Restart (C/R) mechanisms have been widely adopted by many MPI libraries [1 -- 3] to achieve fault-tolerance. However, a major limitation of such mechanisms is the intensive IO bottleneck caused by the need to dump the snapshots of all ...
Comments