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单选题What is the architectural benefit of keeping WebLogic Server transaction log in the database?（）A Oracle does not allow replicating files between data centers, so keeping transaction log in database allows for replication.B Many transactions in WebLogic

题目
单选题
What is the architectural benefit of keeping WebLogic Server transaction log in the database?（）
A

Oracle does not allow replicating files between data centers, so keeping transaction log in database allows for replication.

B

Many transactions in WebLogic are database centric, so keeping log in database makes Two Phase Commit protocol possible.

C

It obviates the need to keep in sync two replication technologies (file and database) between  data centers. The single replication technology is used for frequently changing data.

D

Transaction log in a file system is extremely slow so it cannot be efficiently replicated.

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相似问题和答案

第1题：

Integration between （）with "multi data sources" and（） is defined as Gridlink for RAC （Real Application Clusters）

  • A、 Oracle Weblogic Server； Oracle Database
  • B、 Oracle Weblogic Server clusters； Oracle Database
  • C、 Oracle Weblogic Server clusters； Oracle Database RAC
  • D、 Oracle OC4J； Oracle Database RAC

正确答案:C

第2题：

You are in the middle of a transaction updating a very important table. The machine on which a database wasrunning reboots because of power outage. This caused a database instance failure. Which statement is true inthis situation（）

  • A、The online redo log files and archived redo log files are required to accomplish the recovery.
  • B、The uncommitted transaction will be committed at the next startup of the database instance.
  • C、The uncommitted transaction is rolled back automatically at the next opening of the database.
  • D、The DBA has to perform the recovery on the database to recover the uncommitted transaction

正确答案:C

第3题：

You are the administrator of a SQL Server 2000 computer. The server contains a database named Acct. You purge the Acct database of old records and perform. a full backup. The database now uses 4 GB of space. The database files are configured as shown in the Acct Properties exhibit.

The server has two hard disks that are configured as shown in the Server Configuration exhibit.

The 3 GB transaction log file for the Acct database is stored on drive C. You need to make room for a new database that has a 3 GB data file and a 1 GB transaction log file. You want to optimize database performance on both databases. You also want to minimize administrative overhead.

What should you do?

A．Shrink the empty data file on drive E. Place the new data file and the new log file on drive E.

B．Shrink the empty data file on drive E. Backup and shrink the log file on drive C to 2 GB. Place the new data file on drive E and the new log file on drive C.

C．Shrink the data file on drive D to 1 GB, and then shrink the data file on drive E to 2 GB. Place the new data file on drive D and the new log file on drive E.

D．Shrink and delete the data file on drive C, and then shrink the database files on drives D and E so that they are both 2 GB. Place the new data file and the new log file on drive C.


正确答案：B
解析：Explanation: We must add a new 3GB database with a 1GB transaction log file. Currently we have database that is using 4GB for data and 3GB for the log file. We should place the log file and the data file on two different physical disks out of performance reasons.

The command DBCC SHRINKFILE with the EMPTYFILE option can be used to shrink a datafile to empty. The data will be migrated to the other files in the filegroup. We use this method to free 4.5 GB on Drive E. Then we backup the log file on C and reduce it to 2GB. Then we put the database data file on drive (3GB) and put the log file of the new database on drive C (1GB).

Incorrect answers:
A: It’s better to put the data file and the log file of the new database on two different physical disks out of performance reasons.

C: It’s better to put the data file and the log file of the new database on two different physical disks out of performance reasons.

D: It’s better to put the data file and the log file of the new database on two different physical disks out of performance reasons.

第4题：

What is the architectural benefit of keeping WebLogic Server transaction log in the database?（）

  • A、Oracle does not allow replicating files between data centers, so keeping transaction log in database allows for replication.
  • B、Many transactions in WebLogic are database centric, so keeping log in database makes Two Phase Commit protocol possible.
  • C、It obviates the need to keep in sync two replication technologies (file and database) between  data centers. The single replication technology is used for frequently changing data.
  • D、Transaction log in a file system is extremely slow so it cannot be efficiently replicated.

正确答案:C

第5题：

Which new key architectural element introduced in WebLogic Server l2c should you take  advantage of when designing Disaster Recovery Centers with active - passive mode?（）

  • A、MAN Clusters, because they would allow you to synchronously replicate state in low latency networks 
  • B、WAN Clusters, because they would allow you to asynchronously replicate state in nonlow latency networks.  
  • C、Transaction Log in the database, because you could avoid synchronizing two replication technologies (database and file)  
  • D、Data Guard, because it is the most effective way to replicate a state across locations
  • E、GoldenGate, because it is the most effective way to replicate a state across locations

正确答案:E

第6题：

You work in a company which is named Wiikigo Corp. The company uses SQL Server 2008. You are the administrator of the company database. Now you are in charge of a SQL Server 2008 instance. There is a database named DB1 in the instance. The company stores clients data in DB1. Clients can access their profile data by using a Web application. You must ensure the security of the customer data, you must ensure that even if the backup media is lost, data files, log files and subsequent backups and so on are quite safe. So what action should you perform to achieve this goal?（）

  • A、For both the CustomerDB database and the master database, enable Transparent Database Encryption.
  • B、You should use the built-in encryption functions to encrypt the sensitive data at the cell level. 
  • C、You should make the CustomerDB database accessible only through stored procedures and functions. 
  • D、For the CustomerDB database, enable Transparent Database Encryption and back up the transaction log.

正确答案:D

第7题：

Integration between （） multidata sources and （） is defined as the Grid Link for RAC.

  • A、Oracle WebLogic Server; Oracle Database
  • B、Oracle WebLogic Server clusters; Oracle Database
  • C、Oracle WebLogic Server clusters; Oracle Database RAC
  • D、Oracle OC4J; Oracle Database RAC
  • E、Oracle WebLogic Server; Oracle OC4J

正确答案:C

第8题：

You are the administrator of a SQL Server 2000 computer. You are configuring a database for an inventory application. The hard disks on your server are configured as shown in the exhibit.

The operating system files are located on drive C. Your database will store a maximum of 6 GB of data and requires a maximum of 2 GB of disk space for the transaction log.

You want to optimize database performance. What should you do?

A．Add a 2-GB transaction log to drive D, a 3-GB data file to drive E, and a 3-GB data file to drive F

B．Add a 1-GB transaction log to drive C, a 1-GB transaction log to drive D, a 3-GB data file to drive E, and a 3-GB data file to drive F

C．Add a 1-GB transaction log to drive E, a 1-GB transaction log to drive F, a 3-GB data file to drive E, and a 3-GB data file to drive F

D．Add a 2-GB transaction log to drive F, a 3-GB data file to drive D, and a 3-GB data file to drive E


正确答案：D
解析：Explanation: Basically there are two methods to improve performance in this scenario:

Method 1: put the transaction log file on a separate physical disk.
One way to improve performance and recoverability of your database is to place the data files and the transaction log files on separate disk subsystems, and to use dedicated disks for your data files so that data read and write (I/O) requests are not competing with other I/O requests on those disks. This is (A).

Method 2: data files split across two physical disks
Splitting your data files among a number of disks results in increased I/O performance in particular when multiple controllers are used like in this scenario. This is (D).

To decide which is better we must think about the application. This is an inventory system and we can assume that the queries would be more frequent than additions and update of rows. So we should choose method 2 since it gives the best performance for reading data.

Note: Physical database design involves mapping the logical design onto physical media to allow for the data to be physically accessed and maintained as quickly as possible by taking advantage of the available hardware and software features.

It is important to correctly design the database and to take advantage of hardware and software features early in the development cycle of a database application, because making changes to these components at a later stage it is difficult. Placing log files and the data files on different physical disks, and placing the log file of a drive that does not hold the operating system can improve database performance as it allows the frequently written to log file to exist a disk with its own read/write heads.

Incorrect Answers:
A: In an inventory system data is read more frequently and not so many changes are made to the database. We should optimize the data files not the log file.

B: Placing log files and the data files on different physical disks and placing the log file of a drive that does not hold the operating system can improve database performance as it allows the frequently written to log file to exist a disk with its own read/write heads. In this part of the log file is placed on drive C, which would also hold the operating system.

C: Placing log files and the data files on different physical disks can improve database performance as it allows the frequently written to log file to exist a disk with its own read/write heads. In this solution the log file and the data file are placed on the same physical drive.

第9题：

Which two statements about the background process of the database writer are true（）

  • A、It is possible to have multiple database writers in an Oracle instance.
  • B、It writes dirty buffers， if any， to data files whenever a checkpoint occurs.
  • C、It writes dirty buffers， if any， to data files whenever a transaction commits.
  • D、It writes dirty buffers， if any， to data files before the log writer （LGWR） writes

正确答案:A,B

第10题：

A customer has a critical, performance-sensitive web application that connects to a multimode  Oracle RAC database. Which feature of WebLogic can provide signification benefit?（）

  • A、The Web Session Affinity feature of Active GridLink for RAC
  • B、WebLogic Clustering
  • C、The Transaction Affinity feature of Active GridLink for RAC
  • D、Coherence*Web Session Replication

正确答案:C

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