Concurrency control in distributed database / Various locking protocols in distributed database / Single lock manager and distributed lock manager approaches in handling concurrent transactions
Concurrency control schemes dealt with handling of data as part of
concurrent transactions. Various locking protocols are used for handling
concurrent transactions in centralized database systems. There are no major
differences between the schemes in centralized and distributed databases. The
only major difference is that the way the lock manager should deal with the replicated data. The following topics
discusses about several possible schemes that are applicable to an environment
where data can be replicated in several sites. We shall assume the existence of
the shared and exclusive lock modes.
Locking protocols
Some assumptions:
Our distributed database system consists of n sites (servers/computers
in different locations)
Data are replicated in two or more sites
