| Summary: | 碩士 === 國立臺灣科技大學 === 電子工程學系 === 84 === Global serializability and local autonomy are two important
issues in multidatabase systems. In this thesis, we proposed a
three-level oncurrency control architecture to resolve the
above issues. The global concurrency controller, in the first
level, its the subtransactions of global transactions to all
local sites with a maintained execution order. In the next
level of this architecture, the intermediate concurrency
controller is used to schedule global subtransactions and local
transactions. Its aim is to conduct an execution order which is
consistent with serialization order of global subtransactions.
A directed consistency graph theory is supported by make this
schedule. The local concurrency controller, in the third level,
is only requested to preerve local serializability and
supported by the original DBMS of local site. The correctness
of global serializability of this system architecture is
proved. Finally, In a failure prone environment, it need to
preserve the atomicity of transactions by the two phase commit
protocol, add states and recovery operations in the directed
consistency graph to preserve local serializability and global
serializabilty when transactions are recovered.
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