关于oracle调优

时间：2021-01-08 10:47:49 收藏：0 阅读：0

场景1:查询时间过长

select u.*,t.*

(select sum(l.all_pl2)

from TABLE_A l

where 1 = 1

and l.tx_dt <= ‘20201223‘

and u.investor_id = l.investor_id) as sum_all_pl2

from TABLE_C u

inner join (select t2.*

from (select t.*

rank() over(partition by investor_id order by tx_dt desc) rowno

from TABLE_B t

where t.tx_dt <= ‘20201223‘) t2

where 1 = 1

and t2.rowno = 1) t3 on u.investor_id = t3.investor_id

where 1 = 1

order by HEX(CONVERT( a.create_date USING GBK ))

select count(1) from TABLE_A;--结果集1104207

select count(1)from TABLE_B;--结果集7257

1.查看表是否有索引，为关联字段添加索引

create index idx_tablieatxdtinvid on TABLE_A (INVESTOR_ID, TX_DT);

create index idx_tablieatxdt on TABLE_A (TX_DT);

create index idx_tablieainvid on TABLE_A (INVESTOR_ID);

2.表字段的索引主要针对数值型的varchar2或者number有效。

3.排序字段最好使用数值的varchar2或者number。尽量不使用非数字排序（yyyy-dd-mm，uuid，中英文等）

4.关联字段的类型最好统一，尽量不要用varchar2和number关联（varchar2的数值和number字段关联，减少oracle的隐式转换）

5.主键可以使用封装的@getNextSequence方法获取