Top 10 Oracle RAC (Real Application Cluster) And Performance Tuning Interview Questions Answers

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  • Post last modified:April 12, 2023

Q 1: What is Oracle RAC?

Oracle RAC (Real Application Clusters) is a high-availability solution that allows multiple servers to access a single database simultaneously. It provides a scalable and fault-tolerant platform for mission-critical applications.

Q 2: What is RAC and what are the various benefits of using RAC architecture?

RAC or Real Application Cluster allows the database to be installed across multiple servers forming a cluster and sharing the storage structure at the same time. This prevents the database from a single point of failure as one or the other instance will always stay up even if the other fails. Using RAC helps as following

  • Maintaining high availability of the system.
  • Managing workload with the least expenses.
  • Scalability & agility

Q 3: What is difference between Performance Tuning and Tuning Advisor in Oracle?

Performance tuning is the process of optimizing the performance of a database system by analyzing and adjusting various system parameters such as memory allocation, disk I/O, and CPU usage. The goal is to improve the response time and throughput of the system.

The SQL Tuning Advisor in Oracle is a tool that helps to optimize SQL statements by analyzing the SQL execution plan and providing recommendations for tuning. It can identify performance problems and suggest changes to improve performance.

Q 4: How would you differentiate between cluster and grid?

Clustering is an integral part of grid infrastructure and focuses on a specific objective.

While grid, which may or may not consist of multiple clusters, possesses a wider framework that enables sharing of storage systems, data resources, and remaining others across different geographical locations.

A cluster will have single ownership but the grid can have multiple ownership based on the number of clusters it holds.

Q5: How do you monitor the performance of an Oracle database?

There are several tools and techniques to monitor the performance of an Oracle database, such as:

  • Oracle Enterprise Manager (OEM)
  • Oracle Performance Analyzer (PA)
  • Automatic Workload Repository (AWR)
  • SQL Trace and TKPROF

Q 6: How can a single instance environment be converted into the RAC environment and how will they be different?

Answer: Single instance can be converted into RAC using one of the below methods:

  • Enterprise Manager
  • DBCA i.e. Database Configuration Assistant
  • RCONFIG Utility

Single Instance environment Vs RAC Environment Parameters

ParametersSingle Instance EnvironmentRAC Environment
MemoryInstance will have dedicated SGAEvery instance will have separate SGA
Access to physical filesOnly one instance will access data files and control files.Data files and Control Files are shared across all instances.
Flash Recovery LogAccessed by single instance.Shared by multiple instances.
Redo LogsDedicated to single instance.Only one instance can write at a time but others can read data during recovery or
archiving process.

Q 7: what are the different areas where we can perform tuning?

Performance can be enhanced by tuning any of the below areas:

  • Database design.
  • Memory allocation.
  • Disk I/Os.
  • Database contention.
  • OS level (CPU).

Q 8: What are the different tools that are provided by Oracle to assist performance monitoring?

Answer: Various tools include:

  • AWR(Automatic Workload Repository)
  • ADDM(Automated Database Diagnostics Monitor)
  • OEM(Oracle Enterprise Manager)

Q 9: What is a Recovery Catalog?

Answer: A recovery catalog is a database schema that holds the metadata used by RMAN for restoration and recovery processes. It basically stores information on

  • Data files & their backup files.
  • Archived Redo Logs & their backup sets.
  • Stored scripts
  • Incarnation
  • Backup history

Q 10: What is table partitioning and why is it required?

Answer: It is a process of dividing a table into smaller chunks so as to make data retrieval easy and quick. Each piece will be known as a partition and can be accessed separately. Apart from tables, indexes can also be partitioned.

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