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()