100+ Oracle Database Administrator Interview Questions and Answers

Oracle database architecture consists of multiple components like instance, memory structures, and physical storage.

• Oracle database architecture includes instance, memory structures, and physical storage.

• Instance consists of background processes and memory structures like SGA and PGA.

• Physical storage includes data files, control files, and redo log files.

• Oracle database architecture allows for scalability, high availability, and performance tuning.

SGA is a shared memory area that stores data and control information for Oracle instance. Shared pool is a part of SGA that stores SQL statements and data dictionary cache.

• SGA is a fixed size memory area allocated at instance startup

• SGA contains database buffer cache, redo log buffer, shared pool, etc.

• Shared pool stores frequently used SQL statements and data dictionary cache

• Shared pool can be resized dynamically using ALTER SYSTEM command

Yes, I have worked on Oracle Dataguard.

• I have experience in configuring and managing Oracle Dataguard for disaster recovery.

• I have performed switchover and failover operations to test the failover mechanism.

• I have monitored and resolved issues related to Dataguard synchronization and network connectivity.

• I have also worked on configuring Active Dataguard for read-only reporting purposes.

Different types of objects in a database include tables, views, indexes, sequences, and stored procedures.

• Tables: Used to store data in rows and columns.

• Views: Virtual tables created by a query.

• Indexes: Improve the performance of queries by allowing quick access to specific rows.

• Sequences: Generate unique numbers.

• Stored Procedures: Precompiled SQL code that can be executed with parameters.

RAC (Real Application Clusters) is a feature in Oracle DBA that allows multiple instances to access a single database simultaneously.

• RAC enables high availability and scalability by distributing the workload across multiple nodes.

• Each node in a RAC environment has its own instance of Oracle Database and shared access to the same database.

• RAC requires a shared storage solution like Oracle ASM (Automatic Storage Management) or a cluster file system.

• RAC environments can be confi...read more

To check DR DC sync, use Data Guard Broker or query V$DATAGUARD_STATS view.

• Use Data Guard Broker to check the status of the standby database and its synchronization with the primary database.

• Query V$DATAGUARD_STATS view to check the redo apply lag and transport lag between the primary and standby databases.

• Check the alert log files of both primary and standby databases for any errors or warnings related to data synchronization.

Configuring RAC involves setting up shared storage, network, and database components on multiple nodes.

• Configure shared storage using ASM or NFS

• Configure network components such as VIP, SCAN, and listener

• Install Oracle Grid Infrastructure and Oracle Database software on all nodes

• Create a RAC database using DBCA or manually

• Configure load balancing and failover using services

• Use shell scripting and SQL scripting to automate tasks

• Perform regular maintenance tasks such as patchin...read more

Controlling interview severance involves managing the process and ensuring a smooth transition for candidates.

• Establish clear criteria for severance to avoid ambiguity.

• Communicate openly with candidates about the process and timelines.

• Provide feedback to candidates post-interview to help them improve.

• Ensure all legal and company policies are followed during severance.

Yes, I have knowledge on cloud computing.

• I have experience working with cloud databases like Oracle Cloud Database

• I am familiar with cloud storage solutions like Amazon S3 and Google Cloud Storage

• I have implemented cloud backup and disaster recovery strategies in previous roles

Yes, I have knowledge on other RDBMS such as MySQL, SQL Server, and PostgreSQL.

• I have experience working with MySQL, including database design and optimization.

• I am familiar with SQL Server and have performed tasks such as backup and recovery.

• I have worked with PostgreSQL and have knowledge of advanced features like partitioning and replication.

Configuration parameters play a crucial role in setting up Data Guard for Oracle databases.

• LOG_ARCHIVE_DEST_1 and LOG_ARCHIVE_DEST_2 are used to specify the locations where archived redo logs are stored.

• FAL_SERVER and FAL_CLIENT parameters are used for automatic recovery in case of a failover.

• DB_UNIQUE_NAME parameter is used to uniquely identify each database in a Data Guard configuration.

• LOG_ARCHIVE_CONFIG parameter is used to specify the configuration for archiving redo log...read more

Data pump utility is used for fast data and metadata movement between databases.

• Used for high-speed data and metadata movement between databases

• Can be used to export and import data and metadata

• Provides parallelism and network-based export and import

• Can be used to move data between different Oracle database versions

• Can be used to move data between different operating systems

• Examples: expdp, impdp

A lean supply chain focuses on minimizing waste and maximizing efficiency in the flow of goods and services.

• Focuses on reducing waste in all aspects of the supply chain

• Emphasizes efficiency in production, transportation, and distribution

• Involves continuous improvement and optimization of processes

• Utilizes tools like Just-In-Time inventory management and Kanban systems

• Examples include Toyota's production system and Dell's direct sales model

Causes of query slowness can include inefficient queries, lack of indexes, outdated statistics, hardware limitations, and network latency.

• Inefficient queries - poorly written queries that do not utilize indexes or join tables unnecessarily

• Lack of indexes - missing indexes on columns frequently used in queries

• Outdated statistics - outdated or inaccurate statistics can lead to poor query execution plans

• Hardware limitations - insufficient memory, CPU, or disk I/O can impact quer...read more

Restoring a database using RMAN involves connecting to the target database, restoring the control file, and recovering the database.

• Connect to the target database using RMAN

• Restore the control file from a backup

• Restore the datafiles and tablespaces

• Recover the database to bring it to a consistent state

• Perform necessary checks and validations after restoration

LNS stands for Log Network Server, responsible for transmitting redo data from the primary database to standby databases. MRP is Managed Recovery Process, used to apply redo data to standby databases.

• LNS is responsible for transmitting redo data from primary to standby databases

• MRP is used to apply redo data to standby databases for data recovery

• LNS and MRP are essential components of Oracle Data Guard for ensuring data protection and availability

Physical files in Oracle DBA refer to the actual files on the operating system that store database data and metadata.

• Physical files include datafiles, control files, redo log files, and archive log files.

• Datafiles store the actual data of the database.

• Control files store metadata about the database structure.

• Redo log files store a record of changes made to the database.

• Archive log files store a copy of redo log files for backup and recovery purposes.

Primary and standby databases can be synced using Data Guard in Oracle.

• Configure Data Guard on primary and standby databases

• Enable redo transport services

• Monitor and resolve any synchronization issues

• Perform switchover or failover when necessary

To start RFS and MRP Service in Oracle Database, you can use the ALTER SYSTEM command.

• Connect to the Oracle Database as a user with SYSDBA or SYSOPER privilege.

• To start RFS (Remote File Server) Service, execute the following command: ALTER SYSTEM SET REMOTE_LISTENER='listener_name' SCOPE=SPFILE;

• To start MRP (Managed Recovery Process) Service, execute the following command: ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION;

Oracle database architecture consists of memory structures, background processes, and physical files.

• Memory structures include SGA and PGA

• Background processes include PMON, SMON, DBWn, LGWR, CKPT, etc.

• Physical files include data files, control files, redo log files, etc.

• Oracle database architecture follows a client-server model

• Oracle database architecture supports multi-tier architecture

Fundamentals of Oracle DB and Architecture

• Oracle Database is a relational database management system (RDBMS)

• It uses SQL (Structured Query Language) for querying and managing data

• Consists of physical and logical structures like data files, tablespaces, and schemas

• Architecture includes components like instance, memory structures, and background processes

Real Application Cluster (RAC) is a cluster database with shared disk architecture.

• RAC allows multiple instances to access a single database simultaneously.

• It provides high availability and scalability.

• RAC uses Oracle Clusterware to manage the cluster.

• Load balancing and failover are automatic in RAC.

• RAC requires additional hardware and software licenses.

A DBA is a database administrator who manages and maintains a company's database system.

• DBA stands for Database Administrator

• They are responsible for managing and maintaining a company's database system

• They ensure data security, backup and recovery, performance tuning, and database design

• Requirements include knowledge of SQL, database architecture, and experience with database management systems

• Certifications such as Oracle Certified Professional (OCP) are often preferred

A database administrator's day-to-day activities involve monitoring, maintaining, and optimizing the database system.

• Monitoring database performance and availability

• Performing backups and recovery operations

• Installing and configuring database software

• Managing user accounts and security

• Optimizing database performance through tuning and indexing

• Troubleshooting and resolving database issues

• Implementing database upgrades and patches

• Collaborating with developers and other IT staff...read more

SGA and PGA are memory structures used by Oracle Database to store data and metadata.

• SGA (System Global Area) is a shared memory area that stores data and control information for the entire database instance.

• PGA (Program Global Area) is a memory area that stores data and control information for a single server process.

• SGA is used to store shared data such as database buffers, shared SQL areas, and redo log buffers.

• PGA is used to store private data such as session-specific var...read more

To add a diskgroup in disks, use the CREATE DISKGROUP command in Oracle ASM.

• Ensure that the disks are initialized and partitioned

• Use the ASMCA (ASM Configuration Assistant) or ASMCMD (ASM Command-Line Utility) to create the diskgroup

• Specify the diskgroup name, redundancy level, and the disks to be included in the diskgroup

• Example: CREATE DISKGROUP dg1 NORMAL REDUNDANCY DISK '/dev/sdb1', '/dev/sdc1'

Oracle Architecture is the structure and components of the Oracle database system.

• Consists of physical and logical structures

• Physical structures include data files, control files, redo log files

• Logical structures include tablespaces, schema objects

• Uses memory structures like SGA and PGA for processing data

• Processes like background processes and server processes handle database operations