Mongo相关

mongo地理位置索引

LBS，存储每个地点的经纬度坐标，搜寻附近的地点，建立地理位置索引可提高查询效率。

mongodb地理位置索引，2d和2dsphere，对应平面和球面。

参考 http://blog.csdn.net/fdipzone/article/details/46285521

mongo地理位置查询：

query：state：0                                                                                //查询条件

             loc：{xxxx}                                                                              //loc为point的地理位置索引

 filter {id": 1,"xxx":1,"longitude":1,"latitude":1,"status":1}  //选择哪些字段

db.xxxx.find(
{   "state" : 1,
loc: { $near : { $geometry : { type : "Point" , coordinates : [120.108753, 30.300193] }  , $maxDistance : 500} }} ,
{"id": 1,"xxx":1,"longitude":1,"latitude":1,"status":1})

参考 http://www.360sdn.com/MongoDB/2015/0413/5627.html https://docs.mongodb.org/manual/reference/command/geoNear/

Mongo集群配置

https://docs.mongodb.com/manual/tutorial/deploy-replica-set/

mongo选举算法

http://iceyao.blog.51cto.com/9426658/1561468