Limitation of memory usage in Asp.net Core

Question

I use IMemoryCache in my project. I wonder what will happen if my app pushes many long-living objects in the cache. Can it occupy all the available memory? Could I globally define the maximum memory for the app?

Answer 1

This was written a year ago so I'm going to assume you're using v1.x.x of the Microsoft.Extensions.Caching.Memory package.

Since there isn't a SizeLimit property in the MemoryCacheOptions like v2.x.x, after digging around into the code for a while I found the following line of documentation.

https://github.com/aspnet/Caching/blob/rel/1.1.2/src/Microsoft.Extensions.Caching.Memory/MemoryCache.cs#L329

/// This is called after a Gen2 garbage collection. We assume this means there was memory pressure.
/// Remove at least 10% of the total entries (or estimated memory?).

Thus the package will eat up as much memory as the OS will allow your code to have. When it reaches that limit it will start compacting (evicting) cache entries.

With v2.x.x you can set the limit manually using SizeLimit property and you can even set the amount of compaction when the limit is hit CompactionPercentage.