奇思妙想的SQL｜兼顾性能的数据倾斜处理新姿势

SELECT /*+MAPJOIN(dim)*/  * 
FROM (SELECT * FROM dwd_tbl) base 
LEFT OUTER JOIN (SELECT * FROM dim_tbl) dim
ON base.dim_key = dim.dim_key

SELECT * 
FROM (SELECT * FROM dwd_tbl) base 
LEFT OUTER JOIN (SELECT * FROM dim_tbl) dim
ON IF(COALESCE(base.dim_key,'')='',CONCAT('HIVE_',RAND()),base.dim_key) = dim.dim_key

SELECT * 
FROM (
    SELECT *,CAST(RAND()*10 AS BIGINT) AS ext_a
    FROM dwd_tbl
) base 
LEFT OUTER JOIN (
    SELECT *
    FROM dim_tbl
    LATERAL VIEW EXPLODE(SPLIT('0;1;2;3;4;5;6;7;8;9',';')) tt AS ext_b
    -- 或者Join一个用于倍数膨胀的小表
) dim
ON  base.dim_key = dim.dim_key
AND base.ext_a   = dim.ext_b

-- Step01:热点数据记录提取
INSERT OVERWRITE TABLE tmp_hot_list PARTITION (dt = '${bizdate}')
SELECT   dim_shop_id AS hot_id
FROM   main_table
WHERE   dt = '${bizdate}'
GROUP BY dim_shop_id
HAVING COUNT(1) > 10000
;

INSERT OVERWRITE TABLE final_result_table PARTITION (dt = '${bizdate}')
-- Step02:热点数据处理,使用MapJoin完成处理
SELECT   /*+MAPJOIN(a2,a3)*/ 
         a1.trade_no    AS trade_no
        ,a1.dim_shop_id AS shop_id
        ,a3.shop_name   AS shop_name
        ,a3.shop_type   AS shop_type
FROM (SELECT * FROM main_table WHERE dt = '${bizdate}') a1 
-- Step02-1:主表用JOIN关联热点表进行热点记录筛选
JOIN (SELECT * FROM tmp_hot_list WHERE dt = '${bizdate}') a2 -- 热点数据清单
ON a1.dim_shop_id = a2.dim_shop_id
-- Step02-2:热点维度数据处理
LEFT OUTER JOIN (
    SELECT /*+MAPJOIN(b2)*/ b1.*
    FROM  (SELECT * FROM dim_table_info WHERE dt = '${bizdate}') b1
    JOIN  (SELECT * FROM tmp_hot_list   WHERE dt = '${bizdate}') b2 -- 热点数据清单
    ON    b1.dim_shop_id = b2.dim_shop_id
) a3
ON    a1.dim_shop_id = a3.dim_shop_id
UNION ALL 
-- Step03:非热点数据处理,使用普通Join完成处理,两张表均需要进行Shuffle
SELECT   /*+MAPJOIN(a12)*/ 
         a11.trade_no    AS trade_no
        ,a11.dim_shop_id AS shop_id
        ,a13.shop_name   AS shop_name
        ,a13.shop_type   AS shop_type
FROM (SELECT * FROM main_table WHERE dt = '${bizdate}') a11 
-- Step03-1:主表用ANTI JOIN关联热点表进行剔除
LEFT ANTI JOIN (SELECT * FROM tmp_hot_list WHERE dt = '${bizdate}') a12
ON a11.dim_shop_id = a12.dim_shop_id
-- Step03-2:非热点维度数据处理
LEFT OUTER JOIN (
    SELECT /*+MAPJOIN(b12)*/ b11.*
    FROM  (SELECT * FROM dim_table_info WHERE dt = '${bizdate}') b11
    LEFT ANTI JOIN  (SELECT * FROM tmp_hot_list WHERE dt = '${bizdate}') b12
    ON    b11.dim_shop_id = b12.dim_shop_id
) a13
ON a11.dim_shop_id = a13.dim_shop_id
;

INSERT OVERWRITE TABLE final_result_table PARTITION (dt = '${bizdate}')
SELECT  /*+SKEWJOIN(a1)*/ 
         a1.trade_no    AS trade_no
        ,a1.dim_shop_id AS shop_id
        ,a2.shop_name   AS shop_name
        ,a2.shop_type   AS shop_type
FROM (SELECT * FROM main_table     WHERE dt = '${bizdate}') a1 
LEFT JOIN (SELECT * FROM dim_table_info WHERE dt = '${bizdate}') a2 
ON    a1.dim_shop_id = a2.dim_shop_id
;

WITH 
-- STEP01:热点Key采集
tmp_hot_pid AS (
    SELECT dim_shop_id,'Y' AS is_hot
    FROM main_table_detail
    WHERE dt = '${bizdate}'
    GROUP BY dim_shop_id
    HAVING COUNT(1) > 100000
)
-- STEP02:维表热点数据打标
,tmp_dim_tbl AS (
    SELECT   /*+MAPJOIN(hot)*/ 
              dim.*
            ,COALESCE(hot.is_hot,'N') AS is_hot
    FROM (
        SELECT *
        FROM dim_table_info
        WHERE dt = '${bizdate}'
    ) dim
    LEFT OUTER JOIN tmp_hot_pid hot 
    ON dim.dim_shop_id = hot.dim_shop_id
)
-- STEP03:明细热点数据打标
,tmp_dwd_tbl AS (
    SELECT /*+MAPJOIN(hot)*/ 
             base.*
            ,COALESCE(hot.is_hot,'N') AS is_hot
    FROM (
        SELECT *
        FROM main_table_detail
        WHERE dt = '${bizdate}'
    ) base 
    LEFT OUTER JOIN tmp_hot_pid hot 
    ON base.dim_shop_id = hot.dim_shop_id
)

-- STEP04:数据合并处理,热点数据用Mapjoin,非热点数据用DISTMAPJOIN
INSERT OVERWRITE TABLE final_result_table PARTITION (dt = '${bizdate}')
SELECT *
FROM (
    -- STEP04-1:非热点数据用DISTMAPJOIN
    SELECT  /*+ DISTMAPJOIN(dim(shard_count=77)) */ 
           dwd_tbl.trade_no   AS trade_no
          ,dwd_tbl.trade_date AS trade_date
          ,dwd_tbl.shop_id    AS shop_id
          ,dim.shop_name      AS shop_name
          ,dim.shop_type      AS shop_type
    FROM (SELECT * FROM tmp_dwd_tbl WHERE is_hot = 'N') dwd_tbl
    LEFT OUTER JOIN (SELECT * FROM tmp_dim_tbl WHERE is_hot = 'N') dim 
    ON dwd_tbl.partner_id = dim.partner_id
    UNION ALL
    -- STEP04-1:热点数据用Mapjoin
    SELECT /*+MAPJOIN(dim)*/ 
           dwd_tbl.trade_no   AS trade_no
          ,dwd_tbl.trade_date AS trade_date
          ,dwd_tbl.shop_id    AS shop_id
          ,dim.shop_name      AS shop_name
          ,dim.shop_type      AS shop_type
    FROM (SELECT *FROM tmp_dwd_tbl WHERE is_hot = 'Y') dwd_tbl
    LEFT OUTER JOIN (SELECT *FROM tmp_dim_tbl WHERE is_hot = 'Y') dim 
    ON dwd_tbl.partner_id = dim.partner_id
) base 
;