1. Apply the query tuning on following query and explain why your modification is more efficient?

 

SELECT S_name, S_Phone, S_Age

FROM STUDENT

WHERE S_Age > 22 OR S_Phone like '0555%’;

 

 

2. Consider the three transactions T1, T2, and T3, and the schedules S1 given below. Draw the serializibility (precedence) graphs for S1 and state whether schedule is serializable or not. If a schedule is serializable, write down the equivalent serial schedule(s).

 

T1: r1(x); r1(z); w1(x)

T2: r2(z); r2(y); w2(z); w2(y)

T3: r3(x); r3(y); w3(y)

 

S1: r1(x); r2(z); r3(x); r1(z); r2(y); r3(y); w1(x); w2(z); w3(y); w2(y)

 

 

3. What is cautious waiting deadlock avoidance algorithm? Explain it.

 

 

1.Apply the query tuning on following query and explain why yourmodification is more efficient?2.SELECT S_name, S_Phone, S_AgeFROM STUDENTWHERE S_Age > 22 OR S_Phone like '0555%’;2. Consider the three transactions T1, T2, and T3, and the schedules S1given below. Draw the serializibility (precedence) graphs for S1 andstate whether schedule is serializable or not. If a schedule isserializable, write down the equivalent serial schedule(s).T1: r1(x); r1(z); w1(x)T2: r2(z); r2(y); w2(z); w2(y)T3: r3(x); r3(y); w3(y)S1: r1(x); r2(z); r3(x); r1(z); r2(y); r3(y); w1(x); w2(z); w3(y); w2(y)3. What is cautious waiting deadlock avoidance algorithm? Explain it.

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