hive 多字段同时count(distinct)优化

1.    需求与现状：

源表：pcup_3month_login_dtl_mes，记录数12亿，文件数300

insert overwrite table pcup_logininfo_tmp partition(data_type = 1)
  select popt_id,
         null as sndaid,
         count(distinct case when login_date>='2012-02-01' and login_date<'2012-05-01' then login_date else null end) as m3_login,
         null as m3_login_top5,
         count(distinct case when login_date>='2012-05-01' and login_date<='2012-05-09' then login_date else null end) as mn_login,
         null as mn_login_top5,
         null as m3_apptype,
         null as mn_apptype,
         count(distinct case when login_date>='2012-02-01' and login_date<'2012-05-01' and apptypeid='1' then login_date else null end) as m3_g_login,
         null as m3_g_login_top5,
         count(distinct case when login_date>='2012-02-01' and login_date<'2012-05-01' and apptypeid='2' then login_date else null end) as m3_l_login,
         null as m3_l_login_top5,
         count(distinct case when login_date>='2012-02-01' and login_date<'2012-05-01' and apptypeid='3' then login_date else null end) as m3_s_login,
         null as m3_s_login_top5,
         count(distinct case when login_date>='2012-02-01' and login_date<'2012-05-01' and apptypeid='4' then login_date else null end) as m3_o_login,
         null as m3_o_login_top5,
         count(distinct case when login_date>='2012-05-01' and login_date<='2012-05-09' and apptypeid='1' then login_date else null end) as mn_g_login,
         null as mn_g_login_top5,
         count(distinct case when login_date>='2012-05-01' and login_date<='2012-05-09' and apptypeid='2' then login_date else null end) as mn_l_login,
         null as mn_l_login_top5,
         count(distinct case when login_date>='2012-05-01' and login_date<='2012-05-09' and apptypeid='3' then login_date else null end) as mn_s_login,
         null as mn_s_login_top5,
         count(distinct case when login_date>='2012-05-01' and login_date<='2012-05-09' and apptypeid='4' then login_date else null end) as mn_o_login,
         null as mn_o_login_top5
  from pcup_3month_login_dtl_mes
  group by popt_id;

 特点：group by 维度少，多字段count(distinct), reduce task非常少(7个)耗时：1个半小时以上

2.    优化思路：

利用unionall+groupby+rownumber代替所有的count(distinct)；

3.    优化后的代码：耗时20分钟左右SET mapred.reduce.tasks = 100;

//初步过滤+去重

create table lxw_test3 as 
select popt_id,login_date,apptypeid 
from pcup_3month_login_dtl_mes 
where login_date>='2012-02-01' and login_date <= '2012-05-09' 
group by popt_id,login_date,apptypeid;

//利用rownumber 函数做去重标记

add jar hdfs://nn.dc.sh-wgq.sdo.com:8020/group/p_sdo_data/udf/snda_udf.jar;
CREATE TEMPORARY FUNCTION row_number AS 'com.snda.hive.udf.UDFrow_number';

                   create table lxw_test4 as 
select type,popt_id,login_date,row_number(type,login_date,popt_id) as rn 
from (
       select type,popt_id,login_date 
       from (
                select 'm3_login' as type,popt_id,login_date  
                from lxw_test3 
                where login_date>='2012-02-01' and login_date<'2012-05-01' 
                union all 
                select 'mn_login' as type,popt_id,login_date 
                from lxw_test3 
                where login_date>='2012-05-01' and login_date<='2012-05-09' 
                union all 
                select 'm3_g_login' as type,popt_id,login_date 
                from lxw_test3 
                where login_date>='2012-02-01' and login_date<'2012-05-01' and apptypeid='1' 
                union all 
                select 'm3_l_login' as type,popt_id,login_date 
                from lxw_test3 
                where login_date>='2012-02-01' and login_date<'2012-05-01' and apptypeid='2' 
                union all 
                select 'm3_s_login' as type,popt_id,login_date 
                from lxw_test3 
                where login_date>='2012-02-01' and login_date<'2012-05-01' and apptypeid='3' 
                union all 
                select 'm3_o_login' as type,popt_id,login_date 
                from lxw_test3 
                where login_date>='2012-02-01' and login_date<'2012-05-01' and apptypeid='4' 
                union all 
                select 'mn_g_login' as type,popt_id,login_date 
                from lxw_test3 
                where login_date>='2012-05-01' and login_date<='2012-05-09' and apptypeid='1' 
                union all 
                select 'mn_l_login' as type,popt_id,login_date 
                from lxw_test3 
                where login_date>='2012-05-01' and login_date<='2012-05-09' and apptypeid='2' 
                union all 
                select 'mn_s_login' as type,popt_id,login_date 
                from lxw_test3 
                where login_date>='2012-05-01' and login_date<='2012-05-09' and apptypeid='3' 
                union all 
                select 'mn_o_login' as type,popt_id,login_date 
                from lxw_test3 
                where login_date>='2012-05-01' and login_date<='2012-05-09' and apptypeid='4' 
       ) x 
       distribute by type,login_date,popt_id sort by type,login_date,popt_id 
) y;

//用普通的聚合函数进行汇总

insert overwrite table pcup_logininfo_tmp partition(data_type = 99) 
select popt_id,
null as sndaid,
sum(case when type = 'm3_login' and rn = 1 then 1 else 0 end) as m3_login,
null as m3_login_top5,
sum(case when type = 'mn_login' and rn = 1 then 1 else 0 end) as mn_login,
null as mn_login_top5,
null as m3_apptype,
null as mn_apptype,
sum(case when type = 'm3_g_login' and rn = 1 then 1 else 0 end) as m3_g_login,
null as m3_g_login_top5,
sum(case when type = 'm3_l_login' and rn = 1 then 1 else 0 end) as m3_l_login,
null as m3_l_login_top5,
sum(case when type = 'm3_s_login' and rn = 1 then 1 else 0 end) as m3_s_login,
null as m3_s_login_top5,
sum(case when type = 'm3_o_login' and rn = 1 then 1 else 0 end) as m3_o_login,
null as m3_o_login_top5,
sum(case when type = 'mn_g_login' and rn = 1 then 1 else 0 end) as mn_g_login,
null as mn_g_login_top5,
sum(case when type = 'mn_l_login' and rn = 1 then 1 else 0 end) as mn_l_login,
null as mn_l_login_top5,
sum(case when type = 'mn_s_login' and rn = 1 then 1 else 0 end) as mn_s_login,
null as mn_s_login_top5,
sum(case when type = 'mn_o_login' and rn = 1 then 1 else 0 end) as mn_o_login,
null as mn_o_login_top5
from lxw_test4 
group by popt_id