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
- STATSPACK
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
| Parameters | Single Instance Environment | RAC Environment |
| Instance | Instance | Multiple |
| Memory | Instance will have dedicated SGA | Every instance will have separate SGA |
| Access to physical files | Only one instance will access data files and control files. | Data files and Control Files are shared across all instances. |
| Flash Recovery Log | Accessed by single instance. | Shared by multiple instances. |
| Redo Logs | Dedicated 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)
- TKPROF
- STATSPACK
- 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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