Question

An operation is said to be __________ if executing it several times in a row gives the same result as executing it once.

(a) Idempotent

(b) Changed

(c) Repetitive

(d) All of the above

I had been asked this question in class test.

This key question is from Lock Release and Undo Operations topic in chapter Recovery System of Database Management

Answer 1

Right option is (a) Idempotent

The best I can explain: Operations such as inserting an entry into a B+-tree may not be idempotent, and the recovery algorithm must therefore make sure that an operation that has already been performed is not performed again.