Question: Why the transactions schedule below is violating two- phase policy? Database Concurrency Control Two-Phase Locking Techniques: The algorithm T1 read_lock (Y); read item (Y);

Why the transactions schedule below is violating two- phase policy? Database Concurrency Control Two-Phase Locking Techniques: The algorithm T1 read_lock (Y); read item (Y); unlock (Y); Time write_lock (X); read item (X); X:=X+Y; write_item (X); unlock (X); T2 read_lock (X); read_item (X): unlock (X); write_lock (Y); read_item (Y); Y:=X+Y; write_item (Y); unlock (Y); Result X=50; Y=50 Nonserializable because it. violated two-phase policy.

Step by Step Solution

★★★★★

3.39 Rating (152 Votes )

There are 3 Steps involved in it

1 Expert Approved Answer

Step: 1 Unlock

Answer In two phase locking there needs to be a fi... View full answer

Question Has Been Solved by an Expert!

Get step-by-step solutions from verified subject matter experts

Step: 2 Unlock

Step: 3 Unlock

Students Have Also Explored These Related Databases Questions!

Find the price of a $1000 par value 10-year bond maturing at par which has coupons at 8% convertible semi-annually and is bought to yield 6% convertible quarterly.

Googles ease of use and superior search results have propelled the search engine to its num- ber one status, ousting the early dominance of competitors such as WebCrawler and Infos- eek. Even later...

The Crazy Eddie fraud may appear smaller and gentler than the massive billion-dollar frauds exposed in recent times, such as Bernie Madoffs Ponzi scheme, frauds in the subprime mortgage market, the...

1. You are required to compare the results of your printed reports and the results of reports of the MYOB assignment book in your MYOB assignment. If it is assumed that two results of the reports are...

(a) From the definition of b, the coefficient of volume expansion (at constant pressure), show that = 1/T for an ideal gas. (b) The experimentally determined value of for N 2 gas at 0 o C is...

Flowers are appropriate gifts for women for many situations but seem to be appropriate for men only when they are ill. Why is this so? How might 1-800-FLOWERS change this?

=+a) Comparing the ratings of a new telephone set on a

Monitoring of Receivables The Russ Fogler Company, a small manufacturer of cordless telephones, began operations on January 1. Its credit sales for the first 6 months of operations were a follows:...

Pear Products Lmited of Shenzhen, China, manufactures and distributes toys throughout South East Asia. Three cubic centimeters (cc) of solvent H300 are required to manufacture each unit of Supermix,...

= Consider the following discrete time two-period market model. The savings account is given by t 5 55 where and are 51 t for t= 0, 1, 2. The stock price is given by So = 1 and S = and S =...

Consider a database used to record the marks that students get in different exams of different course offerings. a. Construct an E-R diagram that models exams as entities, and uses a ternary...

Meranti Sdn Bhd has analysed the costs of producing and selling 5,000 units of its only product to be: Direct materials RM 60,000 Direct labour 40,000 Variable factory overhead 20,000 Fixed factory...

(.) Consider the following three relations A, B, and C for this part: C A Attr Attr2 John A John B Mary A Mary C Mary D ST Attr3 15 30 20 35 50 ? B Attr4 10 20 30 40 50 Attr5 a b C d e (D = John A...

Write a Stored Procedure SP_Report_NEW_Budget using the view you created in Part 1-3). Use CURSOR to write the stored Procedure for the tasks below. does the following tasks: Your Stored Procedure...

A capital investment project you have been asked to analyze has net incremental cash flows, Years 1 through 4 , as listed below. The initial investment required is $ 1 million, and the WACC is 1 1 ....

TRUE OR FALSE? Management should consider the diversity (education, nationality etc.) of its workforce, when planning EMS communication activities

The default rate of Don's new customers has been running at 25 percent. The average sale for each new customer amounts to $750, generating a present value of profit of $300 and a 25 percent chance of...

Prepare a stock card using the following information A company is registered for GST which it pays quarterly, assume GST was last paid on the 30th of June 2019. It uses weighted average cost...

Briefly answer the following questions based on this schema: 1. Suppose you have a view SeniorEmp defined as follows: CREATE VIEW SeniorEmp (sname, sage, salary) AS SELECT E.ename, E.age, E.salary...

Compare exception handling and handling of warnings in embedded SQL, dynamic SQL, JDBC, and SQLJ.

What happens if a page is requested when all pages in the buffer pool are dirty?

__________ are tactile receptors located just beneath the skin that respond to changes in pressure. a. Tactile interneurons b. Oligodendrocytes c. Free nerve endings d. Pacinian corpuscles

Hunters who wear camouflage so that they can blend in with their surroundings are relying on which principle of perception? a. depth perception b. expectancy c. shape constancy d. figureground...

Research has found that taste information is sent to the a. suprachiasmatic nucleus. b. pons and medulla. c. insula and frontal operculum. d. cerebellum and parietal lobe.