LINQ Interview Question #124

How can you identify inefficient LINQ queries in production code?

LINQ Performance, EF Core LINQ, Expressions & Advanced Queries Senior Advanced

Quick Interview Answer

Measure rather than guessing. Inspect generated SQL, database command duration, execution plans, row counts, application traces, and memory behavior. Look for excessive materialization, N+1 queries, repeated execution, unbounded result sets, unnecessary Include calls, and client-side processing.

Detailed Explanation

A LINQ expression should be evaluated by the work it causes, not only by how short or elegant the C# looks.

Code Example

var query = db.Products
    .Where(p => p.IsActive)
    .Select(p => new { p.Id, p.Name });

Console.WriteLine(query.ToQueryString());

// Then use profiling/logging for real execution metrics.