DBMS: CONCURRENCY CONTROL 2 PHASE LOCKING PROTOCOL

Question

T1: r1(x)w1(x)r1(y)w1(y)

T2: r2(y)w2(y)

L is xclusive lock and U is unlock

 

L1(y)L1(X)R1(Y)W1(Y)R1(X)W1(X)U1(X)U1(Y)L2(Y)R2(Y)W2(Y)U2(Y)?

IS THIS SCHEDULE  VALID UNDER A 2 PHASE LOCKING SCHEDULER????

Answer 1

THIS SCHEDULE IS NOT VALID BECAUSE IN 2 PHASE LOCKING AFTER EXECUTING SHRINKING PHASE NO LOCK OPERATION CAN WE PERFORM ALL LOCK OPERATION PERFORM IN GROWING PHASE.