الفهرس 
PrefaceOnly 14 pages are availabe for public view
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Abstract
currency control algorithms achieve abase system. The basic problem in concurrency control
to safeguard the correctness of databases updated by
erleaved transactions. Towards this goal., transaction
ps are submitted as they become ready for execution to
concurrency control manager. The concurrency control
ager grants, postpones or rejects these steps; making
e that it preserves the integrity constraints of the
abase.
Serializability, that is the equivalence to a serial
cution [1], [2], [3], still remains the most popular
serializability
ng one or more of the three basic mechanisms
: locking
idation)[4].
Certification-based concurrency control algorithms
e a higher degree of concurrency compared to other
orithms [4], [5],[6]9 estamp ordering and certification( commit-time [7] at the cost of mere wasted
k due to restarts of queries and updaters. An updater
a query is usually restarted if the value(s) of an