Concurrency-control algorithms and their performance in replicated data-based systems

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:7244974

Singhal, M

Two distributed algorithms are developed to synchronize concurrent updates in replicated data-base systems. Both algorithms use timestamps to perform synchronization. The first algorithm uses knowledge of readsets and writesets of updates to enhance concurrency. It avoids update restarts by having all sites exchange the writeset and timestamp of an update prior to executing it. A variant of this algorithm which reduces blocking delays due to conflicting access by creating multiple versions of data objects is studied. Consequently, it has smaller update response time and higher system throughput. However, it requires more storage because multiple versions of data objects may be kept. The second algorithm is based on a fully-distributed approach to update execution where each site completely executes every update. When a site receives an update from a user,it is transported to all other sites. After it, each site executes that update completely without any exchange of computed values. The fully-distributed nature of second algorithm imparts to it several features such as higher resiliency to different kinds of failures, higher parallelism, fast response to user updates, and low communication overhead. A queueing network model of a replicated data base was developed and used in analytic and simulation performance studies.

• Research Organization: Maryland Univ., College Park (USA)
• OSTI ID: 7244974
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
990210 -- Supercomputers-- (1987-1989)
990300* -- Information Handling
ALGORITHMS
DATA BASE MANAGEMENT
DATA PROCESSING
DISTRIBUTED DATA PROCESSING
MANAGEMENT
MATHEMATICAL LOGIC
NETWORK ANALYSIS
PARALLEL PROCESSING
PROCESSING
PROGRAMMING
QUEUES
SIMULATION