Multiple choice

Suppose a schedule with two transactions $T_1 \& T_2$:

$T_1$ $T_2$
Read (A)
Write (A)
Read (A) commit
Read (A) commit

The above schedule is

  1. cascade less schedule

  2. recoverable schedule

  3. irrecoverable schedule

  4. none of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In the given schedule, T2 reads A after T1 writes A but before T1 commits. This is a dirty read. If T1 were to abort after T2 reads, T2 would have read uncommitted data that cannot be recovered - this is an irrecoverable schedule. A cascadeless schedule would prevent dirty reads, and a recoverable schedule requires transactions to commit only after transactions they read from commit.

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