Using ZLINQ with .NET: Optimized LINQ for high performance queries

As the demand for faster and more efficient collection queries increases in .NET applications, many developers are exploring alternatives to standard LINQ. One such option is ZLINQ - a library that offers a LINQ-compatible API with a focus on high performance and zero allocations. It's perfect for data-heavy systems, real-time services, and modern microservices.

In this article, you'll learn what ZLINQ is, how to use it in a modern .NET project, and when to choose it over standard LINQ.

What is ZLINQ?

ZLINQ refers to performance-focused LINQ alternatives such as StructLINQ, Z.Linq, or similar libraries. These libraries aim to replace System.Linq with an implementation that avoids allocations using struct-based enumerators and optimized query pipelines.

⚠️ Note: "ZLINQ" may refer to different libraries depending on the context. This article uses StructLINQ as a representative example for high-performance LINQ alternatives.

Why choose ZLINQ?

• ✅ Zero heap allocations (perfect for high-performance scenarios)

• ✅ Uses struct enumerators to avoid boxing overhead

• ✅ Up to 10x faster in benchmarks compared to traditional LINQ

• ✅ Fully compatible with existing pipelines and foreach loops

• ✅ Ideal for games, IoT, trading systems, and real-time APIs

• ✅ Better CPU cache locality due to value types

Installation

Install StructLINQ via NuGet:

dotnet add package StructLinq

Or for Z.Linq:

dotnet add package Z.Linq

LINQ vs ZLINQ comparison

Traditional LINQ example

var numbers = Enumerable.Range(0, 1000);
var evenNumbers = numbers.Where(n => n % 2 == 0).ToList();

ZLINQ (StructLINQ) example

using StructLinq;

var numbers = StructEnumerable.Range(0, 1000);
var evenNumbers = numbers
    .Where(x => x % 2 == 0)
    .ToList(); // Still allocates for the list, but enumeration is optimized

// Allocation-free version (no intermediate collections)
var evenSum = StructEnumerable.Range(0, 1000)
    .Where(x => x % 2 == 0)
    .Sum();

How does ZLINQ work?

ZLINQ-style libraries achieve superior performance through:

• ref struct enumerators to avoid heap allocations

• Pipelined execution with value types

• JIT optimizations (especially effective in .NET 6+ and .NET 7+)

• Inlining of delegate calls where possible

• Stack-based enumeration instead of heap-based

Performance benchmark

Performance comparison results:

Where + Sum operations:

• Standard LINQ: ~18 µs

• StructLINQ (ZLINQ): ~3.5 µs ⚡️ (5x faster)

Select + ToList operations:

• Standard LINQ: ~22 µs

• StructLINQ (ZLINQ): ~4.0 µs ⚡️ (5.5x faster)

Memory allocations:

• Standard LINQ: High heap allocations 📈

• StructLINQ (ZLINQ): Zero or minimal allocations 🎯

Benchmark tested in .NET 7 using BenchmarkDotNet with integer arrays of 1000 elements

When to use ZLINQ?

Perfect for:

• Working with large in-memory datasets

• Applications requiring low latency and high throughput

• Hot paths in performance-critical code

• Game development and real-time systems

• Scientific computing and data analysis

• Microservices with high request volumes

Target Environments:

• .NET 5+ (optimal performance)

• .NET 6 or newer (best JIT optimizations)

Considerations before adopting

Potential Drawbacks:

• Slightly more verbose syntax compared to standard LINQ

• Not all LINQ operators are available (depends on the library)

• May require struct-aware refactoring of existing code

• Limited IntelliSense support in some IDEs

• Learning curve for developers unfamiliar with struct-based APIs

Complete example with StructLINQ

using StructLinq;
using System;
using System.Diagnostics;

class Program
{
    static void Main()
    {
        const int dataSize = 1_000_000;
        
        // Traditional LINQ
        var sw = Stopwatch.StartNew();
        var linqResult = Enumerable.Range(0, dataSize)
            .Where(x => x % 5 == 0)
            .Select(x => x * 3)
            .Sum();
        sw.Stop();
        Console.WriteLine($"LINQ result: {linqResult} in {sw.ElapsedMilliseconds}ms");
        
        // StructLINQ (ZLINQ-style)
        sw.Restart();
        var structLinqResult = StructEnumerable.Range(0, dataSize)
            .Where(x => x % 5 == 0)
            .Select(x => x * 3)
            .Sum();
        sw.Stop();
        Console.WriteLine($"StructLINQ result: {structLinqResult} in {sw.ElapsedMilliseconds}ms");
    }
}

Decision matrix: ZLINQ vs traditional LINQ

Choosing between Standard LINQ and ZLINQ/StructLINQ:

Readability & ease of use:

• Standard LINQ: ✅ Simple and intuitive syntax

• ZLINQ/StructLINQ: ⚠️ Slightly more complex, requires struct understanding

Runtime performance:

• Standard LINQ: ⚠️ Moderate performance, good for most cases

• ZLINQ/StructLINQ: ✅ Excellent performance, optimized for speed

Memory allocations:

• Standard LINQ: ⚠️ Can generate high heap allocations

• ZLINQ/StructLINQ: ✅ Near-zero allocations, stack-based

.NET compatibility:

• Standard LINQ: ✅ Full support across all .NET versions

• ZLINQ/StructLINQ: ⚠️ Requires .NET Core/5+ for optimal performance

Development speed:

• Standard LINQ: ✅ Fast prototyping, well-known patterns

• ZLINQ/StructLINQ: ⚠️ Requires more consideration and planning

Maintenance:

• Standard LINQ: ✅ Well-known patterns, easy to maintain

• ZLINQ/StructLINQ: ⚠️ Specialized knowledge needed for team

Migration strategy

When migrating from LINQ to ZLINQ:

1. Profile first - Identify actual performance bottlenecks

2. Start small - Replace hot paths gradually

3. Benchmark everything - Measure real-world performance gains

4. Team training - Ensure team understands struct-based patterns

5. Fallback plan - Keep standard LINQ for complex queries

Connect with me

If you work with modern .NET and want to master performance optimization, C#, DevOps, or system interoperability — let's connect:

• 💼 LinkedIn

• ✍️ Medium

• 💻 Dev.to

• 📬 contato@dopme.io

Final thoughts

ZLINQ, particularly libraries like StructLINQ, represents a powerful tool for developers who need to extract maximum performance from their .NET applications. Whether you're building real-time APIs, high-throughput services, or data-intensive applications, ZLINQ can be a valuable optimization ally.

The key is understanding when the performance benefits justify the added complexity. For most applications, standard LINQ is perfectly adequate. However, when you're dealing with performance-critical scenarios, ZLINQ can provide the edge you need.