ASP.NET Core Web API Interview Question #123

What is connection pooling and how does it affect Web APIs?

Dependency Injection, Services, EF Core, Async & Data Access Mid-Level Intermediate

Quick Interview Answer

ADO.NET database providers normally pool physical database connections. Opening a connection typically obtains one from the pool and closing or disposing it returns it for reuse, reducing connection-establishment cost.

Detailed Explanation

Applications should open connections only as needed and dispose them promptly. Increasing pool sizes is not a substitute for fixing slow queries, long transactions, or excessive database concurrency.

Code Example

// EF Core manages connection use for normal queries.
var product = await _db.Products
    .AsNoTracking()
    .SingleOrDefaultAsync(x => x.Id == id, token);