最近有一个需求,统计每天的新老用户,日活,周活,月活。 
 我们每天的增量数据会加入到hive历史数据表中,包含用户访问网站的一些信息,字段有很多,包括用户唯一标识guid。 
 当然了日活,周活,月活就是一个count(distinct(guid))语句,非常常用的sql。
但是这里的问题是:
A:每天的新老用户应该怎么统计呢? 
 B:这还不简单,判断用户guid是否存在与历史库guid中嘛? 
 A:历史数据几十个T,大概一百亿行,你要每天将当日数据(2~3亿行)与历史数据几亿行进行join判断? 
 B:额,这个,这个,好像不行哦!
是的,历史数据里面是用户网站访问行为,同一个用户在同一天,不同的天都有可能出现,guid在历史表中会有多次。如果直接join,性能很差,实际上是做了很多不必要的工作。
解决方案:
维护一张用户表,里面有4列:guid, starttime, endtime, num,分别是用户的guid,第一次访问时间,最后一次访问时间,访问天数; 
 从某个状态开始,历史表中guid是唯一的; 
 当天数据去重后,与历史库join,如果guid在历史库出现过,则将endtime更新为当天时间,num加一; 
 否则,这是一个新用户,插入历史库,starttime, endtime都为当天时间,num初始值为1。
维护了这么一张用户表后,接下来就可以写hql统计业务了,计算当天新老用户时,只需要与这个历史库进行join就行了(目前为止4千万),当日guid去重后是1千多万,这样就是4千万~1千万的join了,与开始4千万~100亿的join,性能会有巨大提升。
hive历史表的设计与hive相关配置 
 
可以看到这里hive历史表history_helper需要频繁修改,hive表支持数据修改需要在${HIVE_HOME}/conf/hive-site.xml中添加事务支持:
<property> <name>hive.support.concurrency</name> <value>true</value> </property
> <property> <name>hive.exec.dynamic.partition.mode</name> <value>nonstrict</
value> </property> <property> <name>hive.txn.manager</name> <value>
org.apache.hadoop.hive.ql.lockmgr.DbTxnManager</value> </property> <property> <
name>hive.compactor.initiator.on</name> <value>true</value> </property> <
property> <name>hive.compactor.worker.threads</name> <value>1</value> </property
> 
为了提高查询速度,hive历史表与增量表这里都分桶,hive-xite.xml配置:
<property> <name>hive.enforce.bucketing</name> <value>true</value> </property> 
为了提高reduce并行度,也设置一下:
set mapred.reduce.tasks = 50; 
这个最好在hive命令行配置,表明只在当前程序使用该配置,就不要配置配置文件了。 
 历史库建表语句:
create external table if not exists hm2.history_helper ( guid string, 
starttime string, endtime string, numint ) clustered by(guid) into 50 buckets 
storedas orc TBLPROPERTIES ("transactional"="true"); 
当天增量表,保存去重后的guid,建表语句:
create table if not exists hm2.daily_helper ( guid string, dt string ) 
clusteredby(guid) into 50 buckets stored as orc TBLPROPERTIES ("transactional"=
"true"); 
思路
由于这种需要写成定时模式,所以这里用python脚本来实现,将hive查询结果保存到本地文件result.txt,然后python读取result.txt,连接数据库,保存当天的查询结果。
代码
helper.py
#!/usr/bin/python # -*- coding:utf-8 -*- # hive更新历史用户表,日常查询,保存到MySQL import sys
import datetime import commands import MySQLdb # 获取起始中间所有日期 def getDays
(starttime,endtime,regx): datestart=datetime.datetime.strptime(starttime,regx) 
dateend=datetime.datetime.strptime(endtime,regx) days = []while 
datestart<=dateend: days.append(datestart.strftime(regx)) 
datestart+=datetime.timedelta(days=1) return days # 获得指定时间的前 n 
天的年、月、日,n取负数往前,否则往后 def getExacYes(day, regx, n): return 
(datetime.datetime.strptime(day,regx) + 
datetime.timedelta(days=n)).strftime(regx)# 获得距离现在天数的年、月、日,n 
取值正负含义同上,昨天就是getYes(regx,-1) def getYes(regx, n): now_time = 
datetime.datetime.now() yes_time = now_time + datetime.timedelta(days=n) 
yes_time_nyr = yes_time.strftime(regx)return yes_time_nyr # 执行hive命令 def 
execHive(cmd): print cmd res = commands.getstatusoutput(cmd) return res # 
获得当前是星期几 def getWeek(regx): now_time = datetime.datetime.now() week = 
now_time.strftime(regx)return week # 格式化日期,加上双引号 def formatDate(day): return 
"\"" + day + "\"" # 数据保存到mysql def insertMysql(dt, path, tbName, regx): # new, 
dayAll, stay values = [] with open(path) as file: line = file.readline() while 
line: values.append(line.strip()) line = file.readline() dayAll = int(values[1
]) new = float(values[0])/dayAll old = 1 - new # 获取数据库连接 conn = MySQLdb.connect(
"0.0.0.0", "statistic", "123456", "statistic") # 获取游标 cursor = conn.cursor() # 
查询昨天的用户人数 yesDay = getExacYes(dt, regx, -1) sql = 'select dayAll from %s where 
dt = %s'%(tbName, formatDate(yesDay)) try: cursor.execute(sql) except Exception 
as e: print e yesAll = int(cursor.fetchall()[0][0]) stay = float(values[2]) / 
yesAllprint stay # 获取游标 cursor2 = conn.cursor() sql = 'insert into %s\ 
values("%s",%f,%f,%f,%d)'%(tbName, dt, new, old, stay, dayAll) print sql try: 
cursor2.execute(sql) conn.commit()except: conn.rollback() finally: conn.close() 
# 初始化,删除临时表,并且创建 def init(): # 设置分桶环境 cmd = 'source /etc/profile;hive -e \'set 
hive.enforce.bucketing = true;set mapred.reduce.tasks = 50;\'' (status,result) 
= execHive(cmd)# 清除当天的临时表,结果保存 cmd = 'source /etc/profile;hive -e \'drop table 
hm2.daily_helper;\'' (status,result) = execHive(cmd) if status == 0: print 
'%s昨天临时表删除完毕...'%(day) else: print result sys.exit(1) cmd = 'source 
/etc/profile;hive -e \'create table if not exists hm2.daily_helper\ (\ guid 
string,\ dt string\ )\ clustered by(guid) into 50 buckets \ stored as orc 
TBLPROPERTIES ("transactional"="true");\'' (status,result) = execHive(cmd) if 
status ==0: print '%s临时表创建完毕...'%(day) else: print result sys.exit(1) # 主函数入口 if
 __name__ =='__main__': regx = '%Y-%m-%d' resultPath = 
'/home/hadoop/statistic/flash/helper/result.txt' days = getDays('2018-07-01',
'2018-07-20',regx) tbName = 'statistic_flash_dailyActive_helper' for day in 
days: init()# 当天数据去重后保存到临时表daily_helper cmd = 'source /etc/profile;hive -e 
\'insert into hm2.daily_helper select distinct(guid),dt from hm2.helper \ where 
dt = "%s" and guid is not null;\''%(day) print '%s数据正在导入临时表...'%(day) 
(status,result) = execHive(cmd)if status == 0: print '%s数据导入临时表完毕...'%(day) else
:print result sys.exit(1) # guid存在则更新 endtime 与 num cmd = 'source 
/etc/profile;hive -e \'update hm2.history_helper set endtime = "%s",num = num + 
1 \ where guid in (select guid from hm2.daily_helper);\''%(day) print 
'正在更新endtime 与 num...' (status,result) = execHive(cmd) if status == 0: print 
'%s history_helper数据更新完毕'%(day) else : print result sys.exit(1) # 当天新用户 cmd = 
'source /etc/profile;hive -e \'select count(1) from hm2.daily_helper \ where 
guid not in (select guid from hm2.history_helper);\' > %s'%(resultPath) 
(status,result) = execHive(cmd)if status != 0: print result sys.exit(1) # 不存在插入 
cmd ='source /etc/profile;hive -e \'insert into hm2.history_helper\ select 
daily.guid,dt,dt,1 from hm2.daily_helper daily\ where daily.guid not in (select 
guid from hm2.history_helper where guid is not null);\'' print 
'正在插入数据到history_helper表...' (status,result) = execHive(cmd) if status == 0: 
print '%s数据插入hm2.history_helper表完成'%(day) else: print result sys.exit(1) # 当天总人数
 cmd ='source /etc/profile;hive -e \'select count(1) from hm2.daily_helper;\' 
>> %s'%(resultPath) (status,result) = execHive(cmd) if status != 0: print 
result sys.exit(1) # 次日活跃留存 cmd = 'source /etc/profile;hive -e \'select 
count(1) from\ (select guid from hm2.helper where dt = "%s" group by guid) yes\ 
inner join\ (select guid from hm2.helper where dt = "%s" group by guid) today\ 
where yes.guid = today.guid;\' >> %s'%(getExacYes(day, regx, -1), day, 
resultPath) (status,result) = execHive(cmd)if status != 0: print result 
sys.exit(1) # 结果保存到mysql insertMysql(day, resultPath, tbName, regx) print 
'=========================%s hive 
查询完毕,结果保存数据到mysql完成=============================='%(day) 
这是在处理历史数据,然后就是每天定时处理了,在linux crontab里加个定时器任务 
<https://www.cnblogs.com/zoulongbin/p/6187238.html>就好了。
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