LINQ TO Nhibernate Count

Question

I am trying to use LINQ to Nhibernate to get a count on a table in my database. However, the code I am running is pulling back all of the records in the table versus running select count() from table.

Here's my code-

public int GetTotalCount(Func<T, bool> where) {

            IQueryable<T> queryable = this._sessionManager.GetCurrentSession().Linq<T>().Where(where).AsQueryable();
            return queryable.Count();

}

I also tried-

    public int GetTotalCount(Func<T, bool> where)
    {
        IQueryable<T> queryable = this._sessionManager.GetCurrentSession().Linq<T>();
        return queryable.Count(where);
    }

Both pull back the entire dataset versus running a count. Any ideas?

Also, I'm using NHProf to profile it, so I can the query it is running, which is

select * from table

Answer 1

Your where parameter needs to be an Expression<Func<T, bool>>; otherwise you are loading everything in memory and using LINQ-to-objects.

In short:

public int GetTotalCount(Expression<Func<T, bool>> where)
{
    return _sessionManager
        .GetCurrentSession()
        .Linq<T>()
        .Where(where);
        .Count();
}