Dispatchers.Default vs Dispatchers.IO in kotlin Coroutine

Both Dispatchers.Default and Dispatchers.IO are used for managing coroutines in Kotlin, but they cater to different scenarios:

1. Purpose:

• Dispatchers.Default: Designed for CPU-bound tasks. This dispatcher utilizes a limited thread pool matching the number of CPU cores on your system.
• Dispatchers.IO: Optimized for I/O-bound operations like network requests, file access, or database interactions. It employs a larger, configurable thread pool.

2. Thread Pool:

• Dispatchers.Default: Fixed size thread pool. The number of threads directly correlates with the available CPU cores.
• Dispatchers.IO: Elastic thread pool. It can dynamically adjust the number of threads based on workload. By default, it uses either 64 threads or the number of CPU cores, whichever is higher.

3. When to use:

• Dispatchers.Default: Use this for computationally intensive tasks that heavily utilize the CPU.
• Dispatchers.IO: Prefer this for operations that involve waiting for external resources like network calls or disk access.

Key Points:

• Choosing the right dispatcher is crucial for optimal performance in your Kotlin coroutines.
• Dispatchers.Default is not ideal for I/O-bound tasks as it has a limited thread pool, causing potential blocking of the main thread.
• While Dispatchers.IO seems apt for I/O tasks, it's generally recommended to avoid using it for CPU-bound work due to thread pool overhead.

In essence:

• Dispatchers.Default - for CPU power
• Dispatchers.IO - for waiting (I/O)

Remember, these are general guidelines. For specific scenarios, it’s essential to analyze the nature of your coroutine’s work and choose the most suitable dispatcher.