SOLUTION

Transaction Coordinator:- The transaction coordinator at each site in a distributed system coordinates the execution of both local and global transactions initiated at that site. This component or module is not required in centralized DBMSs, as there is only one site in a centralized system. The transaction coordinator at each site performs the following tasks to coordinate the execution of transactions initiated at that local site.

• It starts the execution of the transactions initiated at that site.
• it breaks the transactions into a number of subtransactions and distributes these sub-transactions to the appropriate sites for execution.
• It coordinates the termination of the transactions, which may result in the transactions being. committed at all sites or aborted at all sites.