Is RPC synchronous or asynchronous?

RPC (Remote Procedure Call) can be both synchronous and asynchronous, depending on its implementation and the requirements of the application.

1. Synchronous RPC

• In a synchronous RPC, the client sends a request to the server and waits for the response before continuing execution.
• Characteristics:
  • Blocks the client until the server processes the request and sends the response.
  • Simplifies programming as it behaves like a local function call.
  • May introduce latency due to waiting for network communication and server processing.
• Use Case: Suitable for scenarios where the client must rely on the server's response before proceeding, such as fetching data.

2. Asynchronous RPC

• In an asynchronous RPC, the client sends a request to the server and continues execution without waiting for a response. The server processes the request and sends the response later, often through callbacks or polling.
• Characteristics:
  • Non-blocking; allows the client to perform other tasks while waiting for the response.
  • Adds complexity as the client must handle responses asynchronously.
  • Reduces idle time and improves overall efficiency in systems with high latency.
• Use Case: Ideal for scenarios where the client does not need an immediate response, such as logging or batch processing.

Common Behavior in RPC Frameworks

• Many modern RPC frameworks, like gRPC, support both synchronous and asynchronous modes, allowing developers to choose based on their application’s needs.
• Synchronous RPC is easier to implement but can lead to blocking issues in high-latency networks, whereas asynchronous RPC offers better scalability and responsiveness.

The choice between synchronous and asynchronous RPC depends on the specific requirements of the application, such as latency tolerance, resource utilization, and simplicity of implementation.