Ruby 时间窗口上的Mongo查询未返回预期结果

我将此数据集存储在Mongo中。每个元素都有一个已创建的属性

MyModel.all
=> [#<MyModel _id: "bson_object10", created_at: 2014-04-04 16:19:29 UTC, type: "source",     updated_at: 2014-04-04 16:20:12 UTC>,
 #<MyModel _id: "bson_object11", created_at: 2014-04-04 16:19:29 UTC, type: "source",  updated_at: 2014-04-04 16:20:12 UTC>,
 #<MyModel _id: "bson_object12", created_at: 2014-04-04 16:19:29 UTC, type: "source", updated_at: 2014-04-04 16:20:12 UTC>,
 #<MyModel _id: "bson_object20", created_at: 2014-04-04 16:19:30 UTC, type: "source", updated_at: 2014-04-04 16:20:12 UTC>,
 #<MyModel _id: "bson_object21", created_at: 2014-04-04 16:19:30 UTC, type: "source", updated_at: 2014-04-04 16:20:12 UTC>,
 #<MyModel _id: "bson_object22", created_at: 2014-04-04 16:19:30 UTC, type: "source", updated_at: 2014-04-04 16:20:12 UTC>,
 #<MyModel _id: "bson_object30", created_at: 2014-04-04 16:19:31 UTC, type: "source", updated_at: 2014-04-04 16:20:12 UTC>,
 #<MyModel _id: "bson_object31", created_at: 2014-04-04 16:19:31 UTC, type: "source", updated_at: 2014-04-04 16:20:12 UTC>,
 #<MyModel _id: "bson_object32", created_at: 2014-04-04 16:19:31 UTC, type: "source", updated_at: 2014-04-04 16:20:12 UTC>]

在这个时间窗口中，我希望使用以下查询检索mongodb中的前6个元素：

MyModel.where(
   :created_at.gte => Time.at(payload_range[:start_time].to_i).utc,
   :created_at.lte => Time.at(payload_range[:end_time].to_i).utc
).count()
=> 3

但我得到了前三个。由于某些原因，LTE未按预期工作，并且未包括协调世界时2014-04-04 16:19:30的元素。
我做错了什么

---

谢谢

我猜你在某个地方遇到了分数秒的问题

如果我查看MongoDB shell中的一个文档，我会看到如下内容：

"updated_at" : ISODate("2014-04-03T16:29:01.036Z"),

但当我从Rails控制台查看时，我看到：

updated_at: 2014-04-03 16:29:01 UTC

当然，

'2014-04-03T16:29:01.036'
updated_at: 2014-04-03 16:29:01 UTC

MyModel.where(
   :created_at.gte => Time.at(payload_range[:start_time].to_i).utc,
   :created_at.lt  => Time.at(payload_range[:end_time  ].to_i).utc + 1.second
)