ASP.NET Core 2中Session存储复杂对象是否影响应用性能？

Great question—let’s cut to the chase: Yes, serialization and deserialization do add some performance overhead, but in most real-world scenarios, it’s negligible. Only specific edge cases will cause noticeable slowdowns.

Let’s break down the details, when you should worry, and how to optimize:

What’s the Actual Overhead? #

The performance cost comes from two main places:

• Serialization: Converting your complex object to a JSON string requires traversing all its properties, handling type conversions, and building the final string.
• Deserialization: Parsing the JSON string back into an object means mapping string values to your object’s type, instantiating objects, and populating properties.
• On top of that, larger serialized strings mean more IO overhead when writing/reading from Session storage (whether it’s in-memory, Redis, or another provider).

When Will This Become a Problem? #

You’ll only notice performance hits if:

• Your object is extremely large: Think nested objects with hundreds of properties, huge arrays, or embedded binary data (pro tip: don’t store binary data in Session anyway).
• You’re reading/writing the object constantly: For example, if every request to your app reads or modifies this Session value, the repeated serialization/deserialization will add up.
• You’re using an inefficient setup: If you’ve added custom JSON converters that are slow, or you’re using a less performant serializer than the default Newtonsoft.Json (which ASP.NET Core 2 uses out of the box).

How to Optimize the Performance #

If you do run into bottlenecks, here are practical fixes:

• Trim your object: Only store the properties you actually need in Session. Instead of saving the entire database entity, just save the ID and critical fields—fetch the rest from your database when needed.
• Use a faster serializer: Replace JSON with binary serializers like MessagePack or Protobuf. These produce smaller payloads and serialize/deserialize much faster than JSON. For ASP.NET Core 2, you’ll need to install the relevant NuGet packages (e.g., MessagePack) and adjust your Session code to work with byte arrays instead of strings.
• Reduce read/write frequency: Cache the deserialized object in HttpContext.Items for the duration of the request—this way you don’t re-deserialize it every time you need it in the same request.
• Choose the right Session storage: If you’re using a distributed Session provider (like Redis), smaller serialized payloads mean less network transfer time—so optimizing your object size or serializer becomes even more impactful.

Quick Example: Default JSON vs. MessagePack in ASP.NET Core 2 #

Default JSON Approach

// Store complex object in Session
var myObj = new UserProfile { Id = 123, Name = "Jane Doe", Preferences = new List<string> { "dark mode", "notifications" } };
var json = JsonConvert.SerializeObject(myObj);
HttpContext.Session.SetString("UserProfile", json);

// Retrieve and deserialize
var json = HttpContext.Session.GetString("UserProfile");
var myObj = JsonConvert.DeserializeObject<UserProfile>(json);

Faster MessagePack Approach

// Install the MessagePack NuGet package first
using MessagePack;

// Store as bytes
var myObj = new UserProfile { Id = 123, Name = "Jane Doe", Preferences = new List<string> { "dark mode", "notifications" } };
var bytes = MessagePackSerializer.Serialize(myObj);
HttpContext.Session.Set("UserProfile", bytes);

// Retrieve and deserialize
var bytes = HttpContext.Session.Get("UserProfile");
var myObj = MessagePackSerializer.Deserialize<UserProfile>(bytes);

Final Takeaway #

For most apps targeting ASP.NET Core 2, using JSON serialization for complex objects in Session is totally fine. The overhead is minimal unless you’re dealing with very large objects or extreme request volumes. If you do hit performance issues, the optimization steps above will help you get back on track.

内容的提问来源于stack exchange，提问作者DSP