我们在dataworks执行任何一段sql的时候都会在窗口下方看到不断滚动的日志,除了任务报错,大家会关注到它以外,其他情况下更多会被略过。但是真正想对SQL进行优化,想了解SQL运行的底层逻辑,了解日志是必不可少的。
我们仍然以一段具体的生产环境的SQL为例,来引出我们的正文:
select z1.*
,case when all_cnt > 0 then round( delivered_cnt / all_cnt,4) else null end as delivered_pct
from (
select
y1.y_bt_of_timerk
,y1.m_bt_of_timerk
,y1.country_en
,substr(y1.time_rk,1,10) as time_rk
,count(distinct case when status_id='DELIVERED' then waybill_no else null end ) as delivered_cnt
,count(distinct waybill_no) as all_cnt
from (
select
m2.week_year_id AS y_bt_of_curweek
,m2.week_of_year AS m_bt_of_curweek
,to_char(dateadd(to_date(m2.start_week,'yyyy-mm-dd'),-1,'dd'),'yyyy-mm-dd') as start_week
,to_char(dateadd(to_date(m2.end_week,'yyyy-mm-dd'),-1,'dd'),'yyyy-mm-dd') as end_week
,m1.*
,m4.week_year_id AS y_bt_of_timerk
,m4.week_of_year AS m_bt_of_timerk
from (
select
to_char(dateadd(CURRENT_TIMESTAMP(),-1,'dd'),'yyyy-mm-dd') as date_current
,t1.waybill_no
,t1.start_time
,t5.delivered_time
,t2.order_type as Country_EN
,t2.status_id
,t3.name as status_id_CN
,case when t2.status_id ='DELIVERED' then t5.delivered_time else t1.start_time end as time_rk
--#,case when (substr(t5.delivered_time,1,10) = '1970-01-01' or substr(t5.delivered_time,1,10) = '1969-12-31' ) then t1.start_time else t5.delivered_time end as time_rk
from yht_dws.dws_ilp_ar_billing_detail t1
left join yht_dwd.dwd_uexpress_u_express_order_df t2 on t1.waybill_no = t2.number
and t2.pt='${bizdate}'
left join yht_dw.ods_uexpress_order_status_df t3 on t3.id = t2.status_id --#status_id_CN=订单状态_中文
and t3.pt='${bizdate}'
left join yht_dwd.dwd_ilp_trail_detail t5 on t5.trail_ref1 = t1.waybill_no
and t5.pt ='${bizdate}'
where t1.pt='${bizdate}' and t1.bussiness_type='QLL'
and substr(t1.start_time,1,4) = 2023
and t3.name in ('到达待取','退回仓库','清关中','清关完成','已签收','派送中','销毁包裹','航班抵达','运输中','已出库','包裹丢失','二次派送')
) m1
left join yht_dwd.dim_date m2 on m2.date=m1.date_current --#定位当前周
LEFT JOIN yht_dwd.dim_date m4 ON m4.date=to_char(dateadd(m1.time_rk,1,'dd'),'yyyy-mm-dd') --#定位入库时间的当前周
) y1
where ( y_bt_of_curweek = y_bt_of_timerk and m_bt_of_curweek = m_bt_of_timerk )
group by y1.y_bt_of_timerk
,y1.m_bt_of_timerk
,y1.country_en
,substr(y1.time_rk,1,10)
) z1
而运行的日志如下:
job0 is root job
In Job job0:
root Tasks: M6, M4, M3, M2, M1
J5_2_3_4 depends on: M2, M3, M4
J7_1_5_6 depends on: J5_2_3_4, M1, M6
R8_7 depends on: J7_1_5_6
In Task M2:
Data source: yht_dwd.dwd_uexpress_u_express_order_df/pt=20230628
TS: yht_dwd.dwd_uexpress_u_express_order_df/pt=20230628
Statistics: Num rows: 2.2855571E7, Data size: 6.8566713E9
FIL: AND(ISNOTNULL(number),ISNOTNULL(status_id))
Statistics: Num rows: 1.851301251E7, Data size: 5.553903753000001E9
RS: order: +
nullDirection: *
optimizeOrderBy: False
valueDestLimit: 0
dist: HASH
keys:
number
values:
number (string)
order_type (string)
status_id (string)
partitions:
number
Statistics: Num rows: 1.851301251E7, Data size: 5.553903753000001E9
In Task M3:
Data source: yht_dws.dws_ilp_ar_billing_detail/pt=20230628
TS: yht_dws.dws_ilp_ar_billing_detail/pt=20230628
Statistics: Num rows: 1.5791014E7, Data size: 3.284530912E9
SEL: start_time, waybill_no CONDITION: AND(EQ(bussiness_type,'QLL'),EQ(TODOUBLE(SUBSTR(TOSTRING(start_time),1L,4L)),2023.0),ISNOTNULL(waybill_no))
Statistics: Num rows: 3552978.15, Data size: 3.837216402E8
RS: order: +
nullDirection: *
optimizeOrderBy: False
valueDestLimit: 0
dist: HASH
keys:
waybill_no
values:
start_time (datetime)
waybill_no (string)
partitions:
waybill_no
Statistics: Num rows: 3552978.15, Data size: 3.837216402E8
In Task M4:
Data source: yht_dw.ods_uexpress_order_status_df/pt=20230628
TS: yht_dw.ods_uexpress_order_status_df/pt=20230628
Statistics: Num rows: 27.0, Data size: 5400.0
SEL: id CONDITION: AND(IN(name,'到达待取','退回仓库','清关中','清关完成','已签收','派送中','销毁包裹','航班抵达','运输中','已出库','包裹丢失','二次派送'),ISNOTNULL(id))
Statistics: Num rows: 18.225, Data size: 1822.5000000000002
RS: valueDestLimit: 0
dist: BROADCAST
keys:
values:
id (string)
partitions:
Statistics: Num rows: 18.225, Data size: 1822.5000000000002
In Task J5_2_3_4:
JOIN:
StreamLineRead3 INNERJOIN StreamLineRead4
keys:
0:waybill_no
1:number
probeCandidate: StreamLineRead4
Statistics: Num rows: 3.2888164469353332E13, Data size: 1.341837110349616E16
HASHJOIN:
StreamLineRead2 INNERJOIN MergeJoin1
keys:
0:id
1:status_id
non-equals:
0:
1:
bigTable: MergeJoin1
Statistics: Num rows: 2.9969339872698225E14, Data size: 1.22274906680608752E17
RS: order: +
nullDirection: *
optimizeOrderBy: False
valueDestLimit: 0
dist: HASH
keys:
waybill_no
values:
start_time (datetime)
waybill_no (string)
order_type (string)
status_id (string)
partitions:
waybill_no
Statistics: Num rows: 2.9969339872698225E14, Data size: 9.2305566807910528E16
In Task M1:
Data source: yht_dwd.dim_date
TS: yht_dwd.dim_date
Statistics: Num rows: 4748.0, Data size: 1424400.0
SEL: week_of_year, week_year_id CONDITION: AND(EQ(date,'2023-07-03'),ISNOTNULL(week_of_year),ISNOTNULL(week_year_id))
Statistics: Num rows: 1922.94, Data size: 384588.0
RS: valueDestLimit: 0
dist: BROADCAST
keys:
values:
week_of_year (string)
week_year_id (string)
partitions:
Statistics: Num rows: 1922.94, Data size: 384588.0
SEL: date, week_of_year, week_year_id CONDITION: AND(ISNOTNULL(date),ISNOTNULL(week_of_year),ISNOTNULL(week_year_id))
Statistics: Num rows: 3461.2920000000004, Data size: 1038387.6000000001
RS: valueDestLimit: 0
dist: BROADCAST
keys:
values:
date (string)
week_of_year (string)
week_year_id (string)
partitions:
Statistics: Num rows: 3461.2920000000004, Data size: 1038387.6000000001
In Task M6:
Data source: yht_dwd.dwd_ilp_trail_detail/pt=20230628
TS: yht_dwd.dwd_ilp_trail_detail/pt=20230628
Statistics: Num rows: 1.3612384E7, Data size: 1.470137472E9
FIL: ISNOTNULL(trail_ref1)
Statistics: Num rows: 1.22511456E7, Data size: 1.3231237248E9
RS: order: +
nullDirection: *
optimizeOrderBy: False
valueDestLimit: 0
dist: HASH
keys:
trail_ref1
values:
trail_ref1 (string)
delivered_time (datetime)
partitions:
trail_ref1
Statistics: Num rows: 1.22511456E7, Data size: 1.3231237248E9
In Task J7_1_5_6:
JOIN:
StreamLineRead1 RIGHTJOIN StreamLineRead5
keys:
0:trail_ref1
1:waybill_no
probeCandidate: StreamLineRead5
Statistics: Num rows: 1.835793731581557E21, Data size: 7.636901923379278E23
SEL: waybill_no, order_type country_en, status_id, WHEN(EQ(status_id,'DELIVERED'),delivered_time,start_time) time_rk
Statistics: Num rows: 1.835793731581557E21, Data size: 5.654244693271196E23
HASHJOIN:
Project1 INNERJOIN StreamLineRead6
keys:
0:
1:
non-equals:
0:
1:
bigTable: Project1
Statistics: Num rows: 3.5301211982074395E24, Data size: 1.7933015686893794E27
SEL: waybill_no, country_en, status_id, time_rk, week_of_year, week_year_id, $commonVariable8 _col8 [ $commonVariable8(lazy: true) = TO_CHAR(DATEADD(time_rk,1L,'dd'),'yyyy-mm-dd') ] CONDITION: ISNOTNULL($commonVariable8)
Statistics: Num rows: 3.1771090783866956E24, Data size: 1.9316823196591108E27
HASHJOIN:
Calc4 INNERJOIN StreamLineRead7
keys:
0:_col8,week_year_id,week_of_year
1:date,week_year_id,week_of_year
non-equals:
0:
1:
bigTable: Calc4
Statistics: Num rows: 5.498451118073621E27, Data size: 4.992593615210848E30
SEL: week_year_id y_bt_of_timerk, week_of_year m_bt_of_timerk, country_en, SUBSTR(TOSTRING(time_rk),1L,10L) __gk_3, WHEN(EQ(status_id,'DELIVERED'),waybill_no,null) __agg_0_p0, waybill_no
Statistics: Num rows: 5.498451118073621E27, Data size: 3.299070670844173E30
AGGREGATE: group by:y_bt_of_timerk,m_bt_of_timerk,country_en,__gk_3
UDAF: COUNT(DISTINCT__agg_0_p0)[Deduplicate] __agg_0,COUNT(DISTINCTwaybill_no)[Deduplicate] __agg_1
Statistics: Num rows: 1.8830312048197332E27, Data size: 1.12981872289184E30
RS: order: ++++
nullDirection: ****
optimizeOrderBy: False
valueDestLimit: 0
dist: HASH
keys:
y_bt_of_timerk
m_bt_of_timerk
country_en
__gk_3
values:
y_bt_of_timerk (string)
m_bt_of_timerk (string)
country_en (string)
__gk_3 (string)
__agg_0_p0 (string)
waybill_no (string)
partitions:
y_bt_of_timerk
m_bt_of_timerk
country_en
__gk_3
Statistics: Num rows: 1.8830312048197332E27, Data size: 1.12981872289184E30
In Task R8_7:
AGGREGATE: group by:y_bt_of_timerk,m_bt_of_timerk,country_en,__gk_3
UDAF: COUNT(DISTINCT__agg_0_p0) (__agg_0_count)[Complete],COUNT(DISTINCTwaybill_no) (__agg_1_count)[Complete]
Statistics: Num rows: 1.3746127795184053E27, Data size: 5.718389162796566E29
SEL: y_bt_of_timerk, m_bt_of_timerk, country_en, __gk_3 time_rk, __agg_0 delivered_cnt, __agg_1 all_cnt, WHEN(GT(__agg_1,0L),ROUND(DIV(TODOUBLE(__agg_0),TODOUBLE(__agg_1)),4L),null) delivered_pct
Statistics: Num rows: 1.3746127795184053E27, Data size: 5.828358185158038E29
FS: output: Screen
schema:
y_bt_of_timerk (string)
m_bt_of_timerk (string)
country_en (string)
time_rk (string)
delivered_cnt (bigint)
all_cnt (bigint)
delivered_pct (double)
Statistics: Num rows: 1.3746127795184053E27, Data size: 5.828358185158038E29
想要读懂日志,第一,需要对一些日志中的术语进行熟悉;第二,需要对日志进行分组来一一击破。
job0 is root job
In Job job0:
root Tasks: M6, M4, M3, M2, M1
J5_2_3_4 depends on: M2, M3, M4
J7_1_5_6 depends on: J5_2_3_4, M1, M6
R8_7 depends on: J7_1_5_6
术语含义以及语句释义:
M代表Map Task;R代表Reduce Task;J代表Join Task。
root Tasks 代表虚拟节点Job job0下的第一层节点,即root Tasks都属于无依赖节点,命名规则为:M+数字。
J52_3_4 代表 Join Tasks,命名规则为J+数字下划线后为依赖的任务M2,M3,M4,即只有依赖任务M2,M3和M4完成后,J5_2_3_4才会运行。
R87代表Reduce Tasks,命名规则为R+数字下划线后为依赖的任务J7_1_5_6。
In Task M2:
Data source: yht_dwd.dwd_uexpress_u_express_order_df/pt=20230628
# 数据来源 yht_dwd.dwd_uexpress_u_express_order_df/pt=20230628
TS: yht_dwd.dwd_uexpress_u_express_order_df/pt=20230628
# 扫描表 pt=20230628 分区
Statistics: Num rows: 2.2855571E7, Data size: 6.8566713E9
# 扫描数据行数,扫描数据的字节数
FIL: AND(ISNOTNULL(number),ISNOTNULL(status_id))
# 对number和status_id 做非空的过滤
Statistics: Num rows: 1.851301251E7, Data size: 5.553903753000001E9
# 过滤后的条数和数据的字节数
RS: order: +
# 使用ReduceSinkOperator执行数据分发操作
# order + 升序;- 降序
nullDirection: *
optimizeOrderBy: False
valueDestLimit: 0
dist: HASH
keys:
number
values:
number (string)
order_type (string)
status_id (string)
partitions:
number
Statistics: Num rows: 1.851301251E7, Data size: 5.553903753000001E9
Operator算子含义以及语句释义:
from
语句块的逻辑。explain
结果中会显示输入表的名称(Alias)。select
语句块的逻辑。explain
结果中会显示向下一个Operator传递的列,多个列由逗号分隔。<alias>.<column_name>
。func1(arg1_1, arg1_2, func2(arg2_1, arg2_2))
。where
语句块的逻辑。explain
结果中会显示一个where
条件表达式,形式类似SelectOperator的显示规则。join
语句块的逻辑。explain
结果中会显示哪些表以哪种方式Join在一起。explain
结果中会显示聚合函数的内容。explain
的结果中会显示输出结果的排序方式、分发的Key、Value以及用来求Hash值的列。insert
语句块,explain
结果中会显示目标表名称。limit
语句块的逻辑。explain
结果中会显示limit
数。join
操作。 In Task J7_1_5_6:
JOIN:
StreamLineRead1 RIGHTJOIN StreamLineRead5
keys:
# 两表通过0 1 两个字段来关联
0:trail_ref1
1:waybill_no
probeCandidate: StreamLineRead5
Statistics: Num rows: 1.835793731581557E21, Data size: 7.636901923379278E23
SEL: waybill_no, order_type country_en, status_id, WHEN(EQ(status_id,'DELIVERED'),delivered_time,start_time) time_rk
# 关联后选择的字段为如上
Statistics: Num rows: 1.835793731581557E21, Data size: 5.654244693271196E23
HASHJOIN:
Project1 INNERJOIN StreamLineRead6
keys:
0:
1:
non-equals:
0:
1:
bigTable: Project1
Statistics: Num rows: 3.5301211982074395E24, Data size: 1.7933015686893794E27
SEL: waybill_no, country_en, status_id, time_rk, week_of_year, week_year_id, $commonVariable8 _col8 [ $commonVariable8(lazy: true) = TO_CHAR(DATEADD(time_rk,1L,'dd'),'yyyy-mm-dd') ] CONDITION: ISNOTNULL($commonVariable8)
# CONDITION 过滤$commonVariable8为非空
Statistics: Num rows: 3.1771090783866956E24, Data size: 1.9316823196591108E27
HASHJOIN:
Calc4 INNERJOIN StreamLineRead7
keys:
0:_col8,week_year_id,week_of_year
1:date,week_year_id,week_of_year
non-equals:
0:
1:
bigTable: Calc4
Statistics: Num rows: 5.498451118073621E27, Data size: 4.992593615210848E30
SEL: week_year_id y_bt_of_timerk, week_of_year m_bt_of_timerk, country_en, SUBSTR(TOSTRING(time_rk),1L,10L) __gk_3, WHEN(EQ(status_id,'DELIVERED'),waybill_no,null) __agg_0_p0, waybill_no
Statistics: Num rows: 5.498451118073621E27, Data size: 3.299070670844173E30
AGGREGATE: group by:y_bt_of_timerk,m_bt_of_timerk,country_en,__gk_3
UDAF: COUNT(DISTINCT__agg_0_p0)[Deduplicate] __agg_0,COUNT(DISTINCTwaybill_no)[Deduplicate] __agg_1
Statistics: Num rows: 1.8830312048197332E27, Data size: 1.12981872289184E30
RS: order: ++++
nullDirection: ****
optimizeOrderBy: False
valueDestLimit: 0
dist: HASH
keys:
y_bt_of_timerk
m_bt_of_timerk
country_en
__gk_3
values:
y_bt_of_timerk (string)
m_bt_of_timerk (string)
country_en (string)
__gk_3 (string)
__agg_0_p0 (string)
waybill_no (string)
partitions:
y_bt_of_timerk
m_bt_of_timerk
country_en
__gk_3
Statistics: Num rows: 1.8830312048197332E27, Data size: 1.12981872289184E30
我看大家在写脚本的时候,喜欢用“()”将表括起来,可能想着小学时候数学中的运算顺序,括号中的运算程序是优先进行的。如下图:
而我将脚本修改后,具体如下:
我们通过运行日志来看下,具体的执行结果:
我们可以看到除了几个字段的不一致以外,其他的完全一致,说明大家费劲心思的括号其实对于脚本的优化没有一点作用,而且显得脚本特别凌乱,增加了脚本的不可读性。
因此,学会看日志,掌握sql内部运行的规律,对于脚本的优化至关重要。
原创声明:本文系作者授权腾讯云开发者社区发表,未经许可,不得转载。
如有侵权,请联系 cloudcommunity@tencent.com 删除。
原创声明:本文系作者授权腾讯云开发者社区发表,未经许可,不得转载。
如有侵权,请联系 cloudcommunity@tencent.com 删除。