MongoDB 使用mapreduce完成数据迭代

 

文档结构：

Spcode 
Spname
Consignid
Consname
Region
Regionname
Serviceid
Servicename
Srctermid
Logtime

>每天要做两次分组

#SQL
#天分组
SELECT Spcode, Spname, Consignid, Consname, Region, 
Regionname, Serviceid, Servicename, Srctermid 
FROM mo_log_201208 
WHERE Logtime > "20120823" AND Logtime < "20120824" 
GROUP BY Spcode, Spname, Consignid, Consname, Region, Regionname, Serviceid, Servicename

#MongoDB
#天分组
res = db.runCommand({
	mapreduce:'mo_log_201208',
	query:{Logtime:{$gte:'20120823', $lte:'20120824'}},
	map:function() {
		emit({Spcode:this.Spcode, Spname:this.Spname, 
                Consignid:this.Consignid, Consname:this.Consname, 
                Region:this.Region, Regionname:this.Regionname, 
                Serviceid:this.Serviceid,    
                Servicename:this.Servicename, 
                Srctermid:this.Srctermid}, {count:1});
	},
	reduce:function(key, value) {
		var ret = {count:0};
		ret.count++;
		return ret;
	},
	out:'tmp_mo_spcode_consignid_region_serviceid_201208_1',
	verbose:true
})

#SQL
#月分组
SELECT Spcode, Spname, Consignid, Consname, Region, 
Regionname, Serviceid, Servicename, Srctermid 
FROM mo_log_201208 
GROUP BY Spcode, Spname, Consignid, Consname, Region, Regionname, Serviceid, Servicename

 

#MongoDB
#月分组
res = db.runCommand({
	mapreduce:'mo_log_201208',
	map:function() {
		emit({Spcode:this.Spcode, Spname:this.Spname, 
                Consignid:this.Consignid, Consname:this.Consname, 
                Region:this.Region, Regionname:this.Regionname, 
                Serviceid:this.Serviceid, Servicename:this.Servicename, 
                Srctermid:this.Srctermid}, {count:1});
	},
	reduce:function(key, value) {
		var ret = {count:0};
		ret.count++;
		return ret;
	},
	out:'tmp_mo_spcode_consignid_region_serviceid_201208',
	verbose:true
})

 >随着每天数据量的不断增长, 月分组的执行时间会不断的增加~~

 >为了减少重复的分组操作, 降低分组时间, 用天分组的数据来迭代月分组的数据

#MongoDB

res = db.runCommand({
	mapreduce:'mo_log_201208',
	query:{Logtime:{$gte:'20120823', $lte:'20120824'}},
	map:function() {
		emit({Spcode:this.Spcode, Spname:this.Spname, 
        Consignid:this.Consignid, Consname:this.Consname, 
        Region:this.Region, Regionname:this.Regionname, 
        Serviceid:this.Serviceid, Servicename:this.Servicename, 
        Srctermid:this.Srctermid}, {count:1});
	},
	reduce:function(key, value) {
		var ret = {count:0};
		ret.count++;
		return ret;
	},
	finalize:function(key, value){
		db.tmp_mo_spcode_consignid_region_serviceid_201208.insert({"_id":key, "value":value});
		return value;
	},
	out:'tmp_mo_spcode_consignid_region_serviceid_201208_1',
	verbose:true
})

>Mongodb缺省的主键是_id, 在使用insert或者save的时候, 不会产生重复数据
>insert和save的区别是
    >>insert:当主键重复的时候, 放弃操作
    >>save:当主键重复的时候,执行更新操作