未建立索引排序是出现问题
> db.locations.find().sort({date:-1}) error: { "$err" : "too much data for sort() with no index. add an index or specify a smaller limit", "code" : 10128 }
查看记录总数
> db.locations.count() 253953
建立和查看索引
> db.locations.ensureIndex({"date":1}) > db.locations.getIndexes() [ { "v" : 1, "key" : { "_id" : 1 }, "ns" : "lmiot.locations", "name" : "_id_" }, { "v" : 1, "key" : { "date" : 1 }, "ns" : "lmiot.locations", "name" : "date_1" } ]
查看所有索引
> db.system.indexes.find()