RazorEngine Memory Usage - razorengine

Question

I have created a windows service to build and send emails. I am using the Razor Engine to parse the email templates. I am using a dynamic ExpandoObject to create the model.
My problem is when each email is created and sent the memory is increasing but it is never been released. I have profiled the service with Ants Memory profiler(I haven't used this before) but it is showing the following results:
With Razor Engine
Parsing 200 emails with Razor.Parse(text,model)
Generation 1: 12.9kb
Generation 2: 15.88mb
Large Object Heap: 290.9kb
Unused memory allocated to .NET: 3.375mb
Unmanaged: 69.51mb
Total number of memory fragments: 197
No Razor Engine
Returning 200 emails unparsed text.
Generation 1: 13.87kb
Generation 2: 3.798mb
Large Object Heap: 95.58kb
Unused memory allocated to .NET: 4.583mb
Unmanaged: 44.58mb
Total number of memory fragments: 7
With Razor the biggest generation 2 instances are:
System.Reflection.Emit __FixUpData[] - 2,447,640 live bytes, 3,138 instances
Has anyone any idea why the objects aren't being released and the Generation 2 is growing? Is there a way to have a new instance of the RazorEngine each time I want to parse a template and when its finished it will not be referenced and will go to the GC.
Ive tried creating a new instance of Template service each time I parse a template but this hasnt made a difference
using (ITemplateService templateService = new TemplateService())
{
result = templateService.Parse<ExpandoObject>(text, model);
}

Answer 1

Each time you parse a template, RazorEngine compiles an in-memory assembly.
That can get expensive.
You should re-use your templates as much as possible.

Answer 2

Old question, but to activate the template cache you must supply the "cache" argument to the Parse method (which can/should be the path to your template) :
return RazorViewService.Parse(File.ReadAllText(path), model, null, cache);

Answer 3

If you're using the same template repeatedly call RazorEngine.Compile once then Razor.Run there after to ensure that the template is compiled only once.
Also I believe the memory the RazorEngine seems to leak memory when DEBUG is enabled in a build. Make sure your production code is built with the Release profile i.e. without the DEBUG compiler constant.

Answer 4

When you compile a template, the dynamic assemblies that are created are loaded into the current appdomain. There is no facility to unload them so as you compile more templates, the memory keeps growing.
You can use the IsolatedTemplateService in RazorEngine 3.x to get around this. What it does is load the compiled template into a new appdomain. When that appdomain is garbage collected, the template assemblies loaded into that appdomain are then collected as well. There are some limitations though--such as the inability to use dynamic models (Expando objects) or anonymous models. The model also needs to be serializable.
Check this out from the author of RazorEngine: http://www.fidelitydesign.net/?p=473