Question

Distribute and Parallel Database - Quiz
1. When a participating site S, decides to commit the transaction I upon receiving
the <prepare T> message from the coordinator, it sends
message to the
coordinator site.
a) <prepare T>
b) <commit T>
c) <ready T>
d) <abort T>​

Answer 1

Answer:

your answer is option b

hope it will help you.....

Answer 2

Answer:

The option c is the correct answer

Explanation for correct answer:

• According to the two-phase commit protocol, if a site is ready for committing a transaction that was already initiated by a coordinator with a <prepare T> message, it will write a <ready T> message into its log, store in its stable storage, and send the same to the coordinator site.

Explanation for incorrect answer:

• In a two-phase commit, we assume that each site logs actions at that site, but there is no global log.
• The coordinator(Ci), plays a vital role in doing confirmation whether the distributed transaction would abort or commit.
• In this protocol messages are made to send between the coordinator(Ci) and the other sites.
• As each message is sent, its logs are noted at each sending site, to aid in recovery should it be necessary.