[ont.events] U of T Comp. Sci. seminar, Friday, July 19

clarke@utcsri.UUCP (Jim Clarke) (07/15/85)

Philip A. Bernstein, Wang Institute

	will give a Computer Systems Seminar

on Friday, July 19, at 11:00 a.m.,
in room 1105 of the Sandford Fleming Building, 10 King's College Road:

"Concurrency control and recovery in replicated distributed databases"

Abstract:
In a replicated distributed database, some data items may be stored at
multiple sites.  The main motivation for replicated data is improved
reliability.  By storing important data at multiple sites, the database
system can operate even though some sites have failed.

Unfortunately, standard concurrency control algorithms for synchronizing
access to a single copy database do not work correctly for replicated
databases when sites can fail and recover.  In this talk, I'll give a new
characterization of the complex synchronization problems that arise, and
I'll describe a new algorithm that does work correctly and is efficient.
I'll briefly compare the algorithm to quorum consensus, the other popular
approach for synchronizing access to replicated data.