Entity Framework Core: Advanced Query Optimization Techniques for Complex Scenarios in 2024

Entity Framework Core (EF Core) is a friend of every developer. However, as applications grow in complexity, developers often face performance challenges. This article is all about EF Core query optimization techniques, backed by benchmarks.

1. Understanding EF Core Query Execution

Before proceeding with optimization techniques, it’s important to understand how EF Core processes queries in an ASP.NET environment. This knowledge forms the foundation for effective optimization.

The Query Lifecycle

1. Query Construction

In this stage, we’re just defining what we want to retrieve. No database interaction has occurred yet.

public async Task<IActionResult> Index()
{
    var query = _context.Products
        .Where(p => p.Category == "Electronics")
        .OrderBy(p => p.Price);

    // Query is not executed yet
    var products = await query.ToListAsync();
    return View(products);
}

2. Expression Tree Building

EF Core takes your LINQ query and builds an expression tree. This is an internal representation of your query that EF Core can analyze and optimize

e.g.

  var orders = await _context.Orders
            .Where(o => o.OrderDate >= DateTime.Now.AddDays(-30))
            .ToListAsync();

SELECT [o].[Id], [o].[OrderDate], [o].[CustomerId], [o].[Total]
FROM [Orders] AS [o]
WHERE [o].[OrderDate] >= @__DateTime_Now_AddDays_0

3. Query Translation

The expression tree is converted into SQL. You can log this SQL for debugging:

public class ApplicationDbContext : DbContext
{
    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.LogTo(Console.WriteLine, LogLevel.Information);
    }
}

4. Query Execution and Result Materialization