|Figure 1 - Execution of Transaction T in a distributed environment|
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(a) Transaction T is initiated at Site A. Hence, Site A is the Transaction Coordinator site according to the information provided and the given figure. Now, the other sites which are participating in Transaction T can execute the routine of 2PC protocol for handling the Coordinator Failure. For explanation, continue with the link.
(b) According the information provided, Site B is one of the participating site in Transaction T. Hence, the algorithm for handling Site Failure can be invoked and the database could be set right. For explanation, continue with the link.
(c) The appropriate solution for this case is to invoke the Handling of Site Failure routine. As Site C reads a <ready T> message, Site C, in any case cannot decide the fate of Transaction T. Hence, it has to approach other sites including the Coordinator site to know the decision on Transaction T.
(d) There are two cases;
- If the Site C has a record with <abort T>, it has to perform an Undo(T)
- If the Site C does not contain any control messages (no abort, commit, or ready), it has to perform an Undo(T)