Forecast for Specification pattern in Domain layer - problems are expected

Data Access Layer - one of the most painful topics.
Writing a good data access layer is not a trivial task. There are an incredible number of examples of implementation, but only a few are adequate.
Is it possible to consider the implementation of the template Repository - DAL?
That's what MS offers msdn.microsoft.com/en-us/library/ff649690.aspx

And here is the local work habrahabr.ru/post/52173
The options are pretty normal.
But when I see

“The repository is the facade to access the database.”

...
I prefer the Domain Laye r division - Repository - Storage Laye r (just terms)
Layer Members

Domain layer

Aggregation root

- martinfowler.com/bliki/DDD_Aggregate.html (in simple terms - the object model object that the Repository knows about)

Query

(actually about him) - necessarily formed in terms of the Domain

Repository

His Majesty

Repository

- martinfowler.com/eaaCatalog/repository.html

Mapper

- martinfowler.com/eaaCatalog/mapper.html (knows how to convert the Storage entity to Aggregation root and vice versa )

Wow

- martinfowler.com/eaaCatalog/unitOfWork.html (without this thing, there is no room for error, but there is one with it)

Storage layer

Storage entity

- this is not short.
And so DAL is 6 (5 if Mapper is considered part of the Repository) blocks, each of which plays an important role.
The request is just filtering options. As a request to the Repository, I really like the idea of ​​Specification www.codeproject.com/Articles/670115/Specification-pattern-in-Csharp There is also habrahabr.ru/post/171559 .
Creating separate classes of filters is work so-so, but when you start to use all this

query  = CarSpecifications.ByMark( mark ).
                 And( CarSpecifications.ByColor( color ).Not() ) ;
cars = carRepository.Get(query);

, . , , CarSpecifications.

x=>x.GroupName == groupName - :

public class UserQueryExtensions 
{
   public static IQueryable<User> WhereGroupNameIs(this IQueryable<User> users, strin name) 
   {
       return users.Where(u => u.GroupName == name);
   }
}

10 , .

Or Not. DI.
. , ( ,
new ExpressionSpecification(o => o.BrandName == BrandName.Samsung);)
, Repository .)
.
( Aggregation root).
, . – . Specification ,
, Repository ISpecification<D> Predicate<S> ?
.
S S -> D () D . , , .
: , , 50 .
S, GetAll… OutOfMemory.

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50 + 50 + 50 * n , =
( , , ) ( , SQL Dos ).
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, , m ,
50 / m + 50 + 50 * n , = .

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P.S.

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