Question

In ________ no two aborts occur unless two concurrent transactions update the same data item.

(a) Multiversion scheme

(b) Timestamp protocol

(c) Lock based protocol

(d) Snapshot isolation

I have been asked this question in a job interview.

My question is taken from Multiversion Schemes, Snapshot Isolation in portion Concurrency Control of RDBMS

Answer 1

The correct option is (d) Snapshot isolation

Easy explanation: In snapshot isolation no two aborts occur unless two concurrent transactions update the same data item. This makes snapshot isolation attractive but it does not ensure serializability.