Strange Behavior with mongoid date range query. - Rails 3 - ruby-on-rails

Question

I am running in very strange date range query problem. When I use DateTime.now.utc option to query database, the query date for DateTime.now is different that my current DateTime.now(i.e. one that's returned on console.)
My mogoid.yml uses-
use_utc: true
I have my named scope like this -
scope :running_auctions, {
:where => { :end_time.gt => DateTime.now.utc },
:order_by => [:end_time, "ASC"]
}
And on console I can do this -
Loading development environment (Rails 3.0.7)
irb(main):001:0> Auction.running_auctions
=> #<Mongoid::Criteria
selector: {:end_time=>{"$gt"=>Fri Jul 22 00:42:38 UTC 2011}},
options: {:sort=>[:end_time, "ASC"]},
class: Auction,
embedded: false>
Notice that my date here is Fri Jul 22 00:42:38 UTC 2011
irb(main):002:0> DateTime.now
=> Fri, 22 Jul 2011 11:42:56 +0530
irb(main):003:0> DateTime.now.utc
=> Fri, 22 Jul 2011 06:12:59 +0000
Notice here that my datetime is Fri, 22 Jul 2011 06:12:59 +0000
What is making query date older than actual current date ? Does mogoid or mongodb doing caching there ?
Please let me know if I am missing something.
UPDATE
Loading development environment (Rails 3.0.7)
irb(main):001:0> Auction.running_auctions(DateTime.now.utc)
=> #<Mongoid::Criteria
selector: {:end_time=>{"$gt"=>Fri Jul 22 01:21:53 UTC 2011}},
options: {:sort=>[:end_time, "ASC"]},
class: Auction,
embedded: false>
irb(main):002:0> DateTime.now.utc
=> Fri, 22 Jul 2011 06:52:03 +0000

Answer 1

You have to use a lambda there. As of now, the DateTime.now.utc is computed at application startup and cached with application code.
You need to write your scope as:
scope :running_auctions, lambda {
{
:where => { :end_time.gt => DateTime.now.utc },
:order_by => [:end_time, "ASC"]
}
}