Shared Server Vs Dedicated Server in Oracle

In this blog post, we will discuss the differences between shared server and dedicated server and help you determine which option is best for your database.

Dedicated Server:

In a dedicated server configuration, each user is allocated a dedicated server process. The server process is dedicated to that user for the duration of their session. This configuration provides a higher degree of control over the database resources and eliminates the need for context switching. Context switching occurs when the operating system switches from one process to another. With a dedicated server configuration, the server process is always available, and there is no need for context switching.

Dedicated servers have several advantages:

1. Predictable Performance: As each user has their dedicated server process, there is a high degree of predictability in terms of database performance. Dedicated servers provide consistent performance regardless of the number of users or the complexity of the queries.

2. Resource Allocation: Dedicated servers allow for the allocation of specific resources to each user, such as CPU and memory. This ensures that each user has the resources they need to perform their tasks efficiently.

3. Simplified Tuning: In a dedicated server configuration, performance tuning is simplified as each user has their dedicated server process. It is easier to isolate and tune specific server processes.

However, dedicated servers also have some disadvantages:

1. Cost: Dedicated servers require more hardware resources, which can increase the overall cost of the database.

2. Scalability: As the number of users increases, adding more dedicated servers can become expensive and may not be scalable.

Shared Server:

In a shared server configuration, multiple users share a set of server processes. When a user connects to the database, they are assigned a dispatcher process. The dispatcher process manages the user's connection and directs SQL requests to a shared server process. The shared server process is then responsible for processing the user's SQL request.

Shared servers have several advantages:

1. Resource Efficiency: Shared servers are more resource-efficient than dedicated servers. The server processes are shared among multiple users, which reduces the overall resource requirements.

2. Scalability: Shared servers are highly scalable, and additional server processes can be added as the number of users increases.

3. Cost: Shared servers require fewer hardware resources, which can reduce the overall cost of the database.

However, shared servers also have some disadvantages:

1. Performance: As server processes are shared among multiple users, there can be a decrease in performance, especially when many users are accessing the database simultaneously.

2. Complexity: Shared server configurations are more complex than dedicated server configurations. The need for dispatcher and shared server processes can make the configuration more challenging to manage.

Which One to Choose?

When deciding whether to use shared server or dedicated server architecture, there are several factors to consider. If you have a large number of client connections and want to conserve system resources, shared server architecture may be the better choice. If you have a smaller number of clients or need the best performance for individual clients, dedicated server architecture may be the better choice.

Ultimately, the choice between shared server and dedicated server architecture depends on your specific needs and workload. Both options have their own advantages and disadvantages, and it's important to carefully evaluate your requirements before making a decision.