
Distributed Concurrency Control
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Formally, distributed serializability can be defi ned as follows. Consider S is the union of all
local serializable schedules S1, S2,. . . , Sn respectively in a distributed system. Now, the global
schedule S is said to be distributed serializable, if for each pair of confl icting operations Oi and
Oj from distinct transactions Ti and Tj respectively from different sites, Oi precedes Oj in the total
ordering S, and if and only if Ti precedes Tj in all of the local schedules where they appear together.
To attain serializability, a DDBMS must incorporate synchronization techniques that control the
relative ...