Question

I am developing an ASP MVC application using Entity Framework. I was thinking of writing code to cache the object returned by ModelBuilder (as is recommended by several sources), but then I ran into this on Scott Gu’s blog:

“The OnModelCreating method above will be called the first time our NerdDinners class is used within a running application, and it is passed a “ModelBuilder” object as an argument. The ModelBuilder object can be used to customize the database persistence mapping rules of our model objects. We’ll look at some examples of how to do this below.

“EF only calls the “OnModelCreating” method once within a running application – and then automatically caches the ModelBuilder results. This avoids the performance hit of model creation each time a NerdDinners class is instantiated, and means that you don’t have to write any custom caching logic to get great performance within your applications.”

Does this mean that EF automatically caches the ModelBuilder object, and I don’t have to write code to do it, or is this something that is only done if the OnModelCreating method is overridden, or … ??

Answer 1

From the Entity Framework Blog regarding performance improvements in EF 4

Model Caching

There is some cost involved in
discovering the model, processing Data
Annotations and applying fluent API
configuration. To avoid incurring this
cost every time a derived DbContext is
instantiated the model is cached
during the first initialization. The
cached model is then re-used each time
the same derived context is
constructed in the same AppDomain.
Model caching can be turned off by
setting the CacheForContextType
property on ModelBuilder to ‘false’ in
the OnModelCreating method.

So the answer is yes for Entity Framework 4.0