What advantage would you get if you increase the length of time during which the undo information would be stored in the database？（）A、roll back of large transactionsB、roll forward to redo a transactionC、data concurrency for large updatesD、read consistency

第1题：

You observe that database performance has degraded over a period of time. While investigating the reason， you find that the size of the database buffer cache is not large enough to cache all the needed data blocks.  Which advisory component would you refer to， in order to determine the required size of the database buffer cache？（） 

• A、Memory Advisor
• B、Segment Advisor
• C、SQL Tuning Advisor
• D、SQL Access Advisor
• E、Automatic Database Diagnostic Monitor （ADDM）

第2题：

Which two operations require undo data？（）

• A、committing a transaction
• B、rolling back a transaction
• C、recovering from failed transactions
• D、recording a transaction to redo log files
• E、rolling forward during instance recovery

第3题：

You are working on the 24X7 database with high transaction volume， to ensure faster instance recovery on your database you set the FAST_START_MTTR_TARGET initialization parameter to a very low value. What effect it will have on the database？（）

• A、The database performance would be enhanced.
• B、The redo log files would be get filled more frequently.
• C、The overall database performance would be degraded.
• D、The mean time to recover （MTTR） would be increased.

第4题：

You work as a database administrator for Supportcenter.cn. You received the following error while working on your database： ORA-01555： snapshot too old ，In which situation would you receive such an error？（）

• A、You performed rollback after commit.
• B、If a log switch occurs in your database.
• C、Thearchiverfails to generate an archived log file.
• D、Instance recovery fails to find one of the redo log files.
• E、A long-running query is unable to get read-consistent image.
• F、If you perform manual undo management operations in auto mode.

第5题：

What does the DB_FLASHBACK_RETENTION_TARGET parameter configure？（）  

• A、 An upper limit on how far you can flash back the database，depending on the information in the redo logs
• B、 An upper limit on how far you can flash back the database，depending on the information in the undo tablespace
• C、 The amount of time for which the flashback data is to be kept in the flash recovery area， provided that there is enough space
• D、 The amount of time for which the flashback data is guaranteed to be kept in the undo tablespace，provided that there is enough space

第6题：

You have a database with the following tablespaces： SYSTEM， SYSAUX， UNDO， USERS， TEMP. You want to"roll back" the data in the USERS tablespace to the way it looked yesterday.  Which tablespaces do you need to perform a point-in-time restore operation on in order to complete this task？（） 

• A、 SYSTEM
• B、 SYSAUX
• C、 UNDO
• D、 USERS
• E、 TEMP
• F、 This restore is not possible

第7题：

You work as a database administrator for Certkiller .com. One of the user sessions was terminated abnormally in the middle of a transaction. What does Oracle database do to recover it？（）

• A、Uses undo data for roll forward
• B、Uses Flashback Log for recovery
• C、Uses online redo logs to roll back
• D、Uses undo data to roll back the transaction
• E、Uses Recovery Manager （RMAN） to roll back
• F、Uses the System Monitor （SMON） background process to perform instance recovery

第8题：

Your database instance is currently configured to support 1，500 connections. The Web applicationthat uses the database allows a large number of users to work with the database simultaneously. Someusers of the Web application do not interact with the server all the time.  You want to increase the scalability by configuring the database instance to handle more connections. Asa DBA，  which configuration would you set to support more than 1，500 connections at a time（）

• A、You would configure more listeners for the database.
• B、You would configure the database in shared server mode to use the connection pooling feature.
• C、You would increase the value of the PGA_AGGREGATE_TARGET initialization parameter that assigns more session memory to users.
• D、You would decrease the value of the PRIVATE_SGA resource limit in the profiles used by the users to accommodate more session information.

第9题：

You work as a database administrator for Certkiller .com. The UNDO_RETENTION parameter in your database is set to 1000 and undoretention is not guaranteed. Which statement regarding retention of undo data is correct？（）

• A、Undo data becomes obsolete after 1，000 seconds.
• B、Undo data gets refreshed after 1，000 seconds.
• C、Undo data will be stored permanently after 1，000 seconds.
• D、Committed undo data would be retained for 1，000 seconds if free undo space is available.
• E、Undo data will be retained in the UNDOtablespacefor 1，000 seconds， then it gets movedmovedto the TEMPORARYtablespaceto provide read consistency.

第10题：

You work as a database administrator for Certkiller .com. Users in the Certkiller .com PROD database complain about the slow response of transactions. While investigating the reason you find that the transactions are waiting for the undo segments to be available， and undo retention has been set to zero. What would you do to overcome this problem？（）

• A、Increase the undo return
• B、Create more undo segments
• C、Create another undotablespace
• D、Increase the size of the undotablespace