Oracle Database Administration II (1Z0-083) Free Practice Test — 39 Questions

Question 1

A DBA is tasked with optimizing the performance of a busy e-commerce database. They observe high CPU utilization and frequent waits for the \'log file sync\' event. The database experiences a high volume of transactions, and users are complaining about slow commit times. The DBA suspects that the redo log buffer is not being flushed efficiently. Which parameter is most critical for tuning the redo log buffer flushing mechanism to reduce commit latency?

Accepted Answer

LOG_BUFFER

Question 2

A database administrator is investigating performance issues in a production Oracle database. They notice that the buffer cache hit ratio is consistently below 90%, and AWR reports show a high number of \'db file sequential read\' and \'db file scattered read\' wait events. The DBA suspects that the database buffer cache is not adequately sized to hold frequently accessed data blocks. Which of the following actions would be the most appropriate first step to address this issue?

Accepted Answer

Increase the DB_CACHE_SIZE parameter.

Question 3

A database administrator is troubleshooting a performance issue where specific SQL queries are executing very slowly. Upon investigation using SQL Trace and TKPROF, the DBA identifies that the same SQL statements are being parsed repeatedly, even though they are identical. This indicates a lack of efficient SQL statement caching. Which component within the Oracle SGA is primarily responsible for caching SQL statements to avoid repeated parsing?

Accepted Answer

Library Cache within the Shared Pool.

Question 4

A database administrator is configuring a new Oracle database instance. They are concerned about the potential for instance recovery time in the event of a crash. To minimize the time required for instance recovery, which background process plays a critical role in ensuring that redo information is written to disk promptly and consistently, thereby facilitating a faster roll-forward phase during recovery?

Accepted Answer

Log Writer (LGWR).

Question 5

A database administrator is managing a large Oracle database that experiences significant I/O contention. They are reviewing AWR reports and notice a high number of \'log file parallel write\' wait events. This indicates that LGWR is spending a considerable amount of time writing redo information to the online redo log files. To mitigate this I/O bottleneck and improve commit performance, what is the most effective strategy?

Accepted Answer

Place the online redo log files on faster storage, ideally separate from other I/O-intensive operations.

Question 6

A database administrator is performing a critical patch update on a production Oracle database. To minimize downtime, they decide to use the `SHUTDOWN IMMEDIATE` command. However, after issuing the command, the database remains in the `SHUTDOWN` state for an extended period, and the DBA cannot restart it. Upon reviewing the alert log, they find messages indicating that the database is waiting for transactions to complete. Which shutdown mode would have been more appropriate to ensure a quicker shutdown while still allowing active transactions to finish gracefully?

Accepted Answer

TRANSACTIONAL.

Question 7

A database administrator is investigating a performance issue in a production environment. They observe that the database is experiencing frequent waits for the \'buffer busy waits\' event. This indicates that multiple processes are trying to access the same data block in the buffer cache, and contention is occurring. Which of the following is the most likely cause of this issue, and what is the primary solution?

Accepted Answer

High contention on a specific data block due to frequent DML operations; consider block space management or partitioning.

Question 8

A database administrator is reviewing the SGA configuration of a production database. They notice that the `LARGE_POOL_SIZE` parameter is set to a significant value. In which of the following scenarios would allocating memory to the Large Pool be most beneficial?

Accepted Answer

When using RMAN for backup and restore operations, especially with large backup sets or image copies.

Question 9

A database administrator is troubleshooting a performance issue where users are experiencing slow response times when executing complex analytical queries. AWR reports indicate a high number of \'sorts (disk)\' wait events. This suggests that Oracle is performing sorts that exceed the available memory allocated for sorting operations. Which memory area is primarily responsible for holding sort operations, and what parameter should be tuned to address this issue?

Accepted Answer

Program Global Area (PGA); increase PGA_AGGREGATE_TARGET.

Question 10

A database administrator is reviewing the architecture of a highly available Oracle database. They notice that the database uses multiple control files, and these control files are located on different physical disks. What is the primary benefit of multiplexing control files across different physical disks?

Accepted Answer

To provide redundancy and prevent instance startup failure if one control file is lost or corrupted.

Question 11

A database administrator is tasked with recovering a production database after a media failure where a critical data file was lost. The database is in `ARCHIVELOG` mode, and RMAN is configured to back up both data files and archived redo logs. The DBA needs to restore the lost data file and then apply the necessary redo to bring it to a consistent state. Which RMAN command is essential for applying the archived redo logs to the restored data file during the recovery process?

Accepted Answer

RECOVER DATAFILE.

Question 12

A database administrator is implementing a disaster recovery strategy for a critical Oracle database. They are considering using Oracle Data Guard. Which of the following Data Guard configurations provides the highest level of data protection by ensuring that redo data is written to the standby database before a commit is acknowledged on the primary database?

Accepted Answer

Synchronous Redo Transport.

Question 13

A database administrator is tasked with migrating a large schema from one Oracle database to another. They want to minimize the downtime required for the migration and ensure that the data is transferred efficiently. Which Oracle utility is best suited for this task, offering features like parallelism, compression, and the ability to transfer data over the network?

Accepted Answer

Data Pump (expdp/impdp).

Question 14

A database administrator is investigating a performance issue where a specific table is experiencing excessive locking and blocking, leading to application slowdowns. They use the `V$LOCK` and `V$SESSION` views to identify the blocking sessions and the locks they hold. The DBA observes that a session holds an exclusive (X) lock on a row, and another session is waiting to acquire a shared (S) lock on the same row. Which of the following lock modes would the waiting session typically be trying to acquire to read the row?

Accepted Answer

Shared (S) lock.

Question 15

A database administrator is reviewing the performance of a critical application that uses Oracle Database. They notice that the application experiences intermittent delays, and AWR reports show a high number of \'enqueue\' wait events, specifically related to transaction locks. This indicates that sessions are waiting to acquire locks on database objects. Which of the following is the most appropriate action to investigate and resolve this lock contention?

Accepted Answer

Identify blocking sessions using `V$LOCK` and `V$SESSION`, and analyze the SQL statements they are executing.

Question 16

A database administrator is implementing a new application that requires strict data consistency, where each transaction must see a consistent view of the data as it existed at the start of the transaction, even if other transactions are modifying the data concurrently. Which transaction isolation level should be configured to meet this requirement?

Accepted Answer

SERIALIZABLE.

Question 17

A database administrator is reviewing the performance of a data warehousing system. They notice that complex analytical queries are performing poorly, and AWR reports show a high number of \'table scan rows gotten\' and \'table scan blocks gotten\' statistics. This indicates that the queries are performing full table scans on large tables. The DBA suspects that the optimizer is not choosing the most efficient execution plan. Which of the following actions would be most effective in improving the performance of these analytical queries?

Accepted Answer

Gather up-to-date statistics on the large tables and their relevant columns using DBMS_STATS.

Question 18

A database administrator is implementing a security policy that requires all sensitive data in a specific table to be encrypted. The application should be able to query this data seamlessly without requiring application-level changes to handle encryption and decryption. Which Oracle feature provides transparent encryption and decryption of data at rest?

Accepted Answer

Transparent Data Encryption (TDE).

Question 19

A database administrator is responsible for managing a production database that experiences a sudden crash. Upon investigation, they find that the database instance is down and the alert log indicates an unrecoverable error. The DBA needs to bring the database back online as quickly as possible while ensuring data integrity. Which of the following startup modes would be the most appropriate to initiate the recovery process?

Accepted Answer

MOUNT.

Question 20

A database administrator is concerned about the security of sensitive customer data stored in an Oracle database. They want to implement a mechanism to restrict access to specific rows in a table based on the logged-in user\'s identity, ensuring that each user can only see their own data. Which Oracle security feature is most suitable for implementing this requirement?

Accepted Answer

Virtual Private Database (VPD).

Question 21

A database administrator is performing routine maintenance on a production database. They need to ensure that the database is protected against accidental data loss due to user errors or application bugs. Which of the following Oracle technologies provides a mechanism to recover dropped tables and revert data to a previous point in time without requiring a full database restore?

Accepted Answer

Flashback Table.

Question 22

A database administrator is configuring a new Oracle database instance and needs to manage initialization parameters. They are considering using a Server Parameter File (SPFILE) instead of a traditional Initialization Parameter File (PFILE). What is the primary advantage of using an SPFILE over a PFILE?

Accepted Answer

SPFILE allows for dynamic modification of parameters without restarting the instance.

Question 23

A database administrator is troubleshooting a performance issue where a specific SQL query is executing very slowly. They have identified that the query is performing a full table scan on a large table, and the optimizer is not using an available index. The DBA wants to force the optimizer to use the index for this specific query. Which of the following methods can be used to achieve this?

Accepted Answer

Add a SQL hint to the query.

Question 24

A database administrator is implementing a new security policy that requires all database users to have strong passwords and to change them regularly. They need to configure the database to enforce these password requirements. Which of the following Oracle features can be used to manage password complexity, expiration, and history?

Accepted Answer

Password Profiles.

Question 25

A database administrator is performing a critical database upgrade. They need to ensure that the database can be quickly recovered to a consistent state if the upgrade process fails. Which of the following backup strategies is most crucial to have in place before initiating a major upgrade?

Accepted Answer

A full, validated backup of the database.

Question 26

A database administrator is investigating a performance issue in a production environment. They observe that the database is experiencing high CPU utilization, and AWR reports show a significant number of \'library cache lock\' and \'library cache pin\' wait events. This indicates contention for shared SQL statements and PL/SQL objects in the Library Cache. What is the most likely cause of this contention, and what is the recommended solution?

Accepted Answer

Excessive hard parsing of SQL statements; increase SHARED_POOL_SIZE and tune application SQL for reuse.

Question 27

A database administrator is implementing Oracle Data Guard for disaster recovery. They are configuring the redo transport services and need to choose a transport mode that prioritizes data protection over performance. Which redo transport mode ensures that committed transactions on the primary database are guaranteed to be available on the standby database, thus providing zero data loss?

Accepted Answer

Synchronous.

Question 28

A database administrator is investigating a performance issue where a specific SQL query is executing very slowly. They have identified that the query is performing a full table scan on a large table, and the optimizer is not using an available index. The DBA wants to ensure that the optimizer consistently uses the best execution plan for this query, even if statistics change or the database is upgraded. Which Oracle feature is designed to achieve this plan stability?

Accepted Answer

SQL Plan Management (SPM).

Question 29

A database administrator is managing a production database and needs to ensure that sensitive data is protected even if the underlying storage is compromised. They are considering encrypting specific columns that contain personally identifiable information (PII). Which Oracle feature provides column-level encryption?

Accepted Answer

Transparent Data Encryption (TDE) Column Encryption.

Question 30

A database administrator is troubleshooting a performance issue where a specific SQL query is executing very slowly. They have identified that the query is performing a full table scan on a large table, and the optimizer is not using an available index. The DBA wants to ensure that the optimizer consistently uses the best execution plan for this query, even if statistics change or the database is upgraded. Which Oracle feature is designed to achieve this plan stability?

Accepted Answer

SQL Plan Management (SPM).

Question 31

A database administrator is managing a production Oracle database and needs to ensure that the database can be recovered to a specific point in time in case of accidental data deletion or corruption. The database is currently in `NOARCHIVELOG` mode. What is the most critical change required to enable point-in-time recovery?

Accepted Answer

Enable `ARCHIVELOG` mode.

Question 32

A database administrator is investigating performance issues in a data warehousing environment. They observe that complex analytical queries are performing poorly, and AWR reports show a high number of \'buffer busy waits\' on specific index blocks. This suggests contention for index blocks due to concurrent DML operations. Which of the following strategies is most likely to alleviate this contention?

Accepted Answer

Increase the `INITRANS` parameter for the affected indexes.

Question 33

A database administrator is configuring Oracle Data Guard and needs to ensure that the primary database remains available for transactions even if the standby database is temporarily unavailable due to network issues or maintenance. Which redo transport mode offers the best balance between data protection and primary database availability in such scenarios?

Accepted Answer

Asynchronous Redo Transport.

Question 34

A database administrator is tasked with migrating a large Oracle database to a new server. They want to perform this migration with minimal downtime and ensure data integrity. Which Oracle utility is specifically designed for efficient, high-speed data movement between Oracle databases, supporting features like parallelism and network transfer?

Accepted Answer

Data Pump (expdp/impdp).

Question 35

A database administrator is reviewing the SGA configuration of a production database. They notice that the `JAVA_POOL_SIZE` parameter is set to a significant value. In which of the following scenarios would allocating memory to the Java Pool be most beneficial?

Accepted Answer

When running Java Stored Procedures or Java classes within the database.

Question 36

A database administrator is investigating a performance issue where users are experiencing slow response times when executing complex analytical queries. AWR reports indicate a high number of \'sorts (disk)\' wait events. This suggests that Oracle is performing sorts that exceed the available memory allocated for sorting operations. Which memory area is primarily responsible for holding sort operations, and what parameter should be tuned to address this issue?

Accepted Answer

Program Global Area (PGA); increase PGA_AGGREGATE_TARGET.

Question 37

A database administrator is implementing a disaster recovery strategy using Oracle Data Guard. They are configuring the redo transport services and need to choose a transport mode that prioritizes data protection over performance. Which redo transport mode ensures that committed transactions on the primary database are guaranteed to be available on the standby database, thus providing zero data loss?

Accepted Answer

Synchronous.

Question 38

A database administrator is managing a production database and needs to ensure that the database can be recovered to a specific point in time in case of accidental data deletion or corruption. The database is currently in `NOARCHIVELOG` mode. What is the most critical change required to enable point-in-time recovery?

Accepted Answer

Enable `ARCHIVELOG` mode.

Question 39

A database administrator is investigating a performance issue where a specific SQL query is executing very slowly. They have identified that the query is performing a full table scan on a large table, and the optimizer is not using an available index. The DBA wants to force the optimizer to use the index for this specific query. Which of the following methods can be used to achieve this?

Accepted Answer

Add a SQL hint to the query.

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