In an async method, any blocking operations should be avoided.
Using a synchronous method instead of its asynchronous
counterpart in an async method blocks the execution and is considered bad practice for several reasons:
Each thread consumes system resources, such as memory. When a thread is blocked, it’s not doing any useful work, but it’s still consuming these resources. This can lead to inefficient use of system resources.
Blocking threads can limit the scalability of your application. In a high-load scenario where many operations are happening concurrently, each blocked thread represents a missed opportunity to do useful work. This can prevent your application from effectively handling increased load.
Blocking threads can degrade the performance of your application. If all threads in the thread pool become blocked, new tasks can’t start executing until an existing task completes and frees up a thread. This can lead to delays and poor responsiveness.
Instead of blocking, it’s recommended to use the async operator with async methods. This
allows the system to release the current thread back to the thread pool until the awaited task is complete, improving scalability and
responsiveness.
public async Task Examples(Stream stream, DbSet<Person> dbSet)
{
stream.Read(array, 0, 1024); // Noncompliant
File.ReadAllLines("path"); // Noncompliant
dbSet.ToList(); // Noncompliant in Entity Framework Core queries
dbSet.FirstOrDefault(x => x.Age >= 18); // Noncompliant in Entity Framework Core queries
}
public async Task Examples(Stream stream, DbSet<Person> dbSet)
{
await stream.ReadAsync(array, 0, 1024);
await File.ReadAllLinesAsync("path");
await dbSet.ToListAsync();
await dbSet.FirstOrDefaultAsync(x => x.Age >= 18);
}