Monday, October 28, 2013

CHAPTER 6 (CONCURRENCY) DB2 9 Exam 730 certification Dumps


730 CERTIFICATION GUIDE

Q. Which of the following isolation levels will lock all rows scanned to build a result data set?
A. Uncommitted Read
B. Cursor Stability
C. Read Stability
D. Repeatable Read


Q.Application A holds an Exclusive lock on table TAB1 and needs to acquire an Exclusive lock on table TAB2. Application B holds an Exclusive lock on table TAB2 and needs to acquire an Exclusive lock on table TAB1. If lock timeout is set to -1 and both applications are using the Read Stability isolation level, which of the following will occur?
A. Applications A and B will cause a deadlock situation
B. Application B will read the copy of table TAB1 that was loaded into memory when Application A first read it
C. Application B will read the data in table TAB1 and see uncommitted changes made by Application A
D. Application B will be placed in a lock-wait state until Application A releases its lock


Q.A transaction using the Read Stability isolation level scans the same table multiple times before it terminates. Which of the following can occur within this transaction's processing?
A. Uncommitted changes made by other transactions can be seen from one scan to the next.
B. Rows removed by other transactions that appeared in one scan will no longer appear in subsequent scans.
C. Rows added by other transactions that did not appear in one scan can be seen in subsequent scans.
D. Rows that have been updated can be changed by other transactions from one scan to the next.


Q.Two applications have created a deadlock cycle in the locking subsystem. If lock timeout is set to 30 and both applications were started at the same time, what action will the deadlock detector take when it "wakes up" and discovers the deadlock?
A. It will randomly pick an application and rollback its current transaction
B. It will rollback the current transactions of both applications
C. It will wait 30 seconds, then rollback the current transactions of both applications if the deadlock has not been resolved
D. It will go back to sleep for 30 seconds, then if the deadlock still exists, it will randomly pick an application and rollback its current transaction


Q.Application A is running under the Repeatable Read isolation level and holds an Update lock on table TAB1. Application B wants to query table TAB1 and cannot wait for Application A to release its lock. Which isolation level should Application B run under to achieve this objective?
A. Repeatable Read
B. Read Stability
C. Cursor Stability
D. Uncommitted Read


Q.Which of the following DB2 UDB isolation levels will only lock rows during read processing if another transaction tries to drop the table the rows are being read from?
A. Repeatable Read
B. Read Stability
C. Cursor Stability
D. Uncommitted Read


Q.Application A holds a lock on a row in table TAB1. If lock timeout is set to 20, what will happen when Application B attempts to acquire a compatible lock on the same row?
A. Application B will acquire the lock it needs
B. Application A will be rolled back if it still holds its lock after 20 seconds have elapsed
C. Application B will be rolled back if Application A still holds its lock after 20 seconds have elapsed
D. Both applications will be rolled back if Application A still holds its lock after 20 seconds have elapsed


Q.To which of the following resources can a lock NOT be applied?
A. Table spaces
B. Buffer pools
C. Tables
D. Rows
 

Q.Which of the following causes a lock that is being held by an application using the Cursor Stability isolation level to be released?
A. The cursor is moved to another row
B. The row the cursor is on is deleted by the application
C. The row the cursor is on is deleted by another application
D. The row the cursor is on needs to be updated by another application

 
Q.Which of the following modes, when used with the LOCK TABLE statement, will cause the DB2 Database Manager to acquire a table-level lock that prevents other concurrent transactions from accessing data stored in the table while the owning transaction is active?
A. SHARE MODE
B. ISOLATED MODE
C. EXCLUSIVE MODE
D. RESTRICT MODE


Q.An application has acquired a Share lock on a row in a table and now wishes to update the row. Which of the following statements is true?
A. The application must release the row-level Share lock it holds and acquire an Update lock on the row
B. The application must release the row-level Share lock it holds and acquire an Update lock on the table
C. The row-level Share lock will automatically be converted to a row-level Update lock
D. The row-level Share lock will automatically be escalated to a table-level Update lock







Q.Application A wants to read a subset of rows from table TAB1 multiple times. Which of the following isolation levels should Application A use to prevent other users from making modifications and additions to table TAB1 that will affect the subset of rows read?
A. Repeatable Read
B. Read Stability
C. Cursor Stability
D. Uncommitted Read


Q.Which of the following resources can be explicitly locked?
A.Row
B.Page
C.Table
D.Column

Q.Application A issues the following SQL statements within in a single transaction using the Uncommitted Read isolation level:
SELECT * FROM employee WHERE deptno='A00';
UPDATE employee SET salary = salary * 1.1 WHERE deptno='A00';
As long as the transaction has not been committed, which of the following is true for all other applications not running under the Uncommitted Read isolation level?

A.They can read and make changes to data for any employee in department A00.
B.They can read but not make changes to data for any employee in department A00.
C.They must wait until the transaction is committed before accessing data of any employee in department A00.
D.They must wait until application A disconnects before accessing data of any employee in department A00.

Q. Which of the following best describes how locks are used in DB2?
A.To maintain control of updated rows for commit processing
B.To ensure only committed changes are altered by another application
C.To allow two applications to update the same row of data simultaneously
D.To prevent multiple applications from accessing the same data simultaneously

Q. If an application issues the same query more than once in the same Unit of Work, which isolation level will not permit this application to see additional rows inserted by other applications?

 A.Read Stability (RS)
B.Repeatable Read (RR)
C.Uncommitted Read (UR)
C.Cursor Stability (CS)

Q. If DB2 detects a deadlock between application A and application B (each waiting for a lock held by the other one), what action will DB2 take?

A.Rollback the transaction in both applications.
B.Rollback the transaction in one of the two applications.
C.Decrease the lock timeout value for both applications, thereby causing a lock timeout situation.
D.Send a message to let the administrator know of the situation and decide which application or applications should be terminated.

Q. How does DB2 protect the integrity of indexes when data is updated?
A.Locks are acquired on the data.
B.Locks are acquired on index keys.
C.Locks are acquired on index pages.
D.Locks are acquired on index pointers.

Q. Application A currently holds an exclusive lock on a single row and application B tries to access that row. If lock timeout is set to -1 and both applications are using isolation level RS, which of the following will occur?

A.Applications A and B will cause a deadlock situation.
B.Application B will read the previous version of the row.
C.Application B will read the row and see uncommitted changes made by application A.
D.Application B will be placed in a lock-wait state until application A releases its lock.


Q. A table contains a list of all seats available at a football stadium. A seat consists of a section number, a seat number, and whether or not the seat has been assigned. A ticket agent working at the box office generates a list of all unassigned seats. When the agent refreshes the list, it should only change if another agent assigns one or more unassigned seats. Which of the following is the best isolation level to use for this application?
A. Repeatable Read
B. Read Stability
C. Cursor Stability
D. Uncommitted Read

1 comment:

  1. Everything is very open with a precise clarification
    of the challenges. It was definitely informative.
    Your website is very helpful. Thank you for sharing!

    my web site; http://www.biznes.katalog.az.pl/

    ReplyDelete