mongodb sort with skip and limit不根据索引对记录进行排序

Question

我正在尝试使用skip和对 Mongo 进行分页limit。

我想让页面记录按register_time. 在数据库中，记录按索引而不是按 排序register_time。

如何使多页记录（多次跳过）遵循相同的register_time顺序？

db.collection.aggregate(
[ { "$project" : { "os" : "$os", 
                   "register_time" : "$register_time", 
                   "channel" : "$channel", 
                   "event" : "$event", 
                   "user_id" : "$user_id" } }, 
   { "$match" : { "register_time" : 
                { "$gt" : ISODate("2016-06-23T00:00:00Z"), 
                  "$lt" : ISODate("2050-06-25T23:59:00Z") }, 
                  "event" : "Register_with_number", 
                  "channel" : "001" } }, 
   { "$group" : { "_id" : 
                  { "register_time" : "$register_time", 
                    "user_id" : "$user_id", 
                    "os" : "$os", 
                    "channel" : "$channel" }, 
                  "count" : { "$sum" : 1 } } },
   {"$skip":4},
   {"$limit":10}, 
   { "$sort" :  {"_id.register_time" : -1 } } ])

这是skip结果

 { "_id" : { "register_time" : ISODate("2016-06-24T08:49:36Z"), "user_id" : "65675f96", "os" : "Android", "channel" : "040401" }, "count" : 1 }
 { "_id" : { "register_time" : ISODate("2016-06-24T06:29:56Z"), "user_id" : "f61d0572", "os" : "Android", "channel" : "040401" }, "count" : 1 }
 { "_id" : { "register_time" : ISODate("2016-06-24T04:13:31Z"), "user_id" : "d7d1349d", "os" : "Android", "channel" : "040401" }, "count" : 1 }
 { "_id" : { "register_time" : ISODate("2016-06-24T03:40:13Z"), "user_id" : "ecea2908", "os" : "Android", "channel" : "040401" }, "count" : 1 }

这是第二个skip结果：

{ "_id" : { "register_time" : ISODate("2016-06-24T09:05:13Z"), "user_id" : "6fde06a6", "os" : "Android", "channel" : "040401" }, "count" : 1 }
{ "_id" : { "register_time" : ISODate("2016-06-24T07:47:46Z"), "user_id" : "1e5e5712", "os" : "Android", "channel" : "040401" }, "count" : 1 }
{ "_id" : { "register_time" : ISODate("2016-06-24T05:34:55Z"), "user_id" : "47dfaa32", "os" : "Android", "channel" : "040401" }, "count" : 1 }
{ "_id" : { "register_time" : ISODate("2016-06-24T05:15:03Z"), "user_id" : "70960ae2", "os" : "Android", "channel" : "040401" }, "count" : 1 }

如您所见，两个页面的register_time顺序不同。

如何让不同的页面（跳过）遵循一个一致的顺序？谢谢。

Answer 1

你需要移动$sort之前$limit和$skip

这样做$limit你限制了集合中的随机文档，下一个管道条目基于随机输入