Question

我编写了一个SQL查询，为每个 Year-Week-Mine-Product 生成一些统计信息报告。

除了一件事之外，它完全符合要求 - trn.wid-date 不是正确使用的日期。

我应该使用 td.datetime-act-comp-dump 。当我用 td.datetime-act-comp-dump 替换 trn.wid-date 时，它不会给我任何错误，但似乎只是无限期挂起。我昨天让它停了一段时间，它返回时ORA-01652无法在表空间TEMP中将临时段扩展128，尽管从那以后我没有看到这个错误。

考虑到我能够在下面的查询中成功返回 MAX（td.datetime-act-comp-dump），我不明白会导致什么呢？

select to_char(trn.wid_date, 'IYYY') as dump_year,
       to_char(trn.wid_date-7/24, 'IW') as dump_week,
       SUBSTR(trn.train_control_id,1,2) as Mine,
       vcon.product_type_code as Product,
       COUNT(DISTINCT trn.train_control_id) as Trains,
       COUNT(1) as Wagons,
       MIN(trn.wid_date) as Min_WID_Hrs,
       MAX(trn.wid_date) as Max_WID_Hrs,
       MIN(td.datetime_act_comp_dump) as Min_Fin_Dump,
       MAX(td.datetime_act_comp_dump) as Max_Fin_Dump,        
       ROUND(SUM(con.weight_total-con.empty_weight_total),0) as Tot_Tonnes,       
       ROUND(AVG(con.weight_total-con.empty_weight_total),2) as Avg_Tonnes,
       ROUND(MIN(con.weight_total-con.empty_weight_total),2) as Minimum,
       ROUND(PERCENTILE_DISC(0.99) WITHIN GROUP (ORDER BY (con.weight_total-con.empty_weight_total) DESC),2) as "1st",      

from  widsys.consist con
      INNER JOIN widsys.train trn
      USING (train_record_id)
      INNER JOIN tpps.train_details td
      ON trn.train_tpps_id||trn.mine_code = td.train_id||td.mine_code
      INNER JOIN widsys.v_consist_ore_detail vcon
      USING (consist_id)

where trn.direction = 'N'
      and to_char(trn.wid_date, 'IYYY') = 2009
      and to_char(trn.wid_date-7/24, 'IW') = 25

group by to_char(trn.wid_date, 'IYYY'),
         to_char(trn.wid_date-7/24, 'IW'),
         SUBSTR(trn.train_control_id,1,2),
         vcon.product_type_code

order by to_char(trn.wid_date-7/24, 'IW') DESC

为了排除故障，从上面的查询中，我尝试删除与 vcon 相关的所有操作，并将 trn.wid_date 替换为 td.datetime -act-COMP-转储即可。结果是它只报告 Year-Week-Mine 而不是 Year-Week-Mine-Product 。（见下面的查询）

这个新查询实际执行而不仅仅是挂起，但返回一些奇怪的结果并不足够，因为它不会破坏Product上的内容。

select to_char(td.datetime_act_comp_dump, 'IYYY') as dump_year,
       to_char(td.datetime_act_comp_dump-7/24, 'IW') as dump_week,
       SUBSTR(trn.train_control_id,1,2) as Mine,
       --vcon.product_type_code as Product,
       COUNT(DISTINCT trn.train_control_id) as Trains,
       COUNT(1) as Wagons,
       MIN(trn.wid_date) as Min_WID_Hrs,
       MAX(trn.wid_date) as Max_WID_Hrs,
       MIN(td.datetime_act_comp_dump) as Min_Fin_Dump,
       MAX(td.datetime_act_comp_dump) as Max_Fin_Dump,        
       ROUND(SUM(con.weight_total-con.empty_weight_total),0) as Tot_Tonnes,       
       ROUND(AVG(con.weight_total-con.empty_weight_total),2) as Avg_Tonnes,
       ROUND(MIN(con.weight_total-con.empty_weight_total),2) as Minimum,
       ROUND(PERCENTILE_DISC(0.99) WITHIN GROUP (ORDER BY (con.weight_total-con.empty_weight_total) DESC),2) as "1st"       

from  widsys.consist con
      INNER JOIN widsys.train trn
      USING (train_record_id)
      INNER JOIN tpps.train_details td
      ON trn.train_tpps_id||trn.mine_code = td.train_id||td.mine_code
      --INNER JOIN widsys.v_consist_ore_detail vcon
      --USING (consist_id)

where trn.direction = 'N'
      and to_char(td.datetime_act_comp_dump, 'IYYY') = 2009
      and to_char(td.datetime_act_comp_dump-7/24, 'IW') = 25

group by to_char(td.datetime_act_comp_dump, 'IYYY'),
         to_char(td.datetime_act_comp_dump-7/24, 'IW'),
         SUBSTR(trn.train_control_id,1,2)
         --vcon.product_type_code

order by to_char(td.datetime_act_comp_dump-7/24, 'IW') DESC

关于可能出错的任何建议？

干杯，

托米

Answer 1

在没有更多信息的情况下，我唯一能想到的是，datetime_act_comp_dump的{{1}}列未编入索引且train_details为。{1}}。这听起来像是一个非常正常的性能问题，其中某些内容未被编入索引，或者wid_date和train表的大小差别很大，而且您的联接正在爆发。

我不确定您使用的是哪个数据库，但您可能想知道如何运行查询执行计划分析器并查看两个执行计划之间的区别。我怀疑答案是结构性的，或者可能是连接语句中的连接导致了一些特定于数据库的问题。

Answer 2

我设法通过为widsys表创建子查询以及为tpps表创建一个子查询来更快地运行muuuuuu。然后在两列上进行隐式内连接，而不是连接。

SELECT blah FROM (widsys subquery) w, (tpps subquery) t WHERE w.mine_code = t.mine_code and w.train_id = t.train_tpps_id

SQL查询在连接时挂起

2 个答案: