The .NET framework imposes a 32-bit index limit on arrays, capping their size at roughly 2GB. This has been a long-standing pain point for developers working with large datasets, machine learning models, or high-performance computing. A GitHub issue requesting 64-bit array support was ultimately closed as 'won't fix' due to the massive breaking changes it would introduce. This article explores the technical reasons behind this limitation and presents several practical workarounds, including custom data structures, memory-mapped files, and unsafe code techniques. The author provides code examples and performance benchmarks, making it a valuable resource for .NET developers who need to push beyond the built-in array size. Understanding these workarounds is crucial for building scalable, memory-efficient .NET applications.
A deep dive into .NET's array size limits and workarounds for building very large managed arrays.