Question

我使用了以下内容（检查循环中的错误，如果它们存在，我将它们插入表中）：

FOR rec IN (SELECT MAX(t.s_id) as s_id,t.sdate,t.stype,t.snumber,t.code,
            SUM(t.amount) as amount, t... (other fields)
            FROM stable t WHERE t.sdate=p_date AND t.stype=p_type 
                          AND t.snumber=p_num 
            GROUP BY t.sdate,t.snumber,t.stype, t... (other fields)) LOOP  
    v_reason := null;

    BEGIN
      SELECT d.source_id INTO i_source_id FROM mapping m, source d 
      WHERE TO_NUMBER(m.stage)=rec.snumber AND 
            m.month=EXTRACT(MONTH FROM rec.sdate) AND 
            m.year=EXTRACT(YEAR FROM rec.sdate) AND m.desc=d.source_desc AND
            m.month=d.month AND m.year=d.year AND m.name='SOURCE';
    EXCEPTION
      WHEN OTHERS
        THEN 
           e_id := 1;
           v_reason := 'source_id';
    END;

    IF (v_reason IS NULL) THEN
        BEGIN     
          SELECT p.product_id INTO i_product_id FROM mapping m, product p
          WHERE m.stage=rec.code AND 
                m.month=EXTRACT(MONTH FROM rec.sdate) AND 
                m.year=EXTRACT(YEAR FROM rec.sdate) AND 
                m.desc=p.product_name AND m.month=p.month AND 
                m.year=p.year AND m.name='PRODUCT';               
        EXCEPTION
          WHEN OTHERS
            THEN 
               e_id := 2;
               v_reason := 'product_id';
        END;
      END IF;

    --- and 5 more checks from other tables ---
    ---....---

    IF (v_reason IS NULL) THEN
       INSERT INTO tbl_destination(sdate,source_id,product_id,amount, ... and others) 
       VALUES(rec.sdate,i_source_id,i_product_id,NVL(abs(rec.amount),0), ...);  
    ELSE
       INSERT INTO tbl_errors(rec_id,e_id,desc) VALUES(rec.s_id,e_id,v_reason);
    END IF; 
    COMMIT;                         
END LOOP;

对于大量记录（约20000）来说太慢了。求你帮帮我。

Answer 1

在SQL和PLSQL之间来回跳转会带来巨大的开销。在您的情况下，您执行查询，然后对主查询中找到的每个记录执行新查询。由于SQL和PLSQL之间的所有上下文切换以及由于单独的查询更难以优化，这会减慢批次。写一个大查询。优化器可以完成所有的魔术，你只需要一个上下文切换。

执行下一个查询：它返回的每一行都是错误。您只需要读取sourceCount和productCount以查看哪个是问题（或两者）。

要插入错误：

insert into tbl_errors (rec_id, e_id, desc) 
select
  s_id, 
  case 
    when sourceCount <> 1 then 1
    when productCount <> 1 then 2
    when ...
  end as e_id,
  case 
    when sourceCount <> 1 then 'source_id'
    when productCount <> 1 then 'product_id'
    when ...
  end as reason
from
(
    SELECT 
      MAX(t.s_id) as s_id,
      t.sdate,t.stype,t.snumber,t.code,
      SUM(t.amount) as amount, 

      (SELECT count(*) 
      FROM mapping m, source d 
      WHERE 
        TO_NUMBER(m.stage)=rec.snumber AND 
        m.month=EXTRACT(MONTH FROM rec.sdate) AND 
        m.year=EXTRACT(YEAR FROM rec.sdate) AND m.desc=d.source_desc AND
        m.month=d.month AND m.year=d.year AND m.name='SOURCE') as sourceCount,

      (SELECT count(*)
      FROM mapping m, product p
      WHERE 
        m.stage=rec.code AND 
        m.month=EXTRACT(MONTH FROM rec.sdate) AND 
        m.year=EXTRACT(YEAR FROM rec.sdate) AND 
        m.desc=p.product_name AND m.month=p.month AND 
        m.year=p.year AND m.name='PRODUCT') as productCount,

      /* other checks */        

    FROM 
      stable t 
    WHERE 
      t.sdate=p_date AND t.stype=p_type 
      AND t.snumber=p_num 
    GROUP BY 
      t.sdate, t.snumber, t.stype
) x
having 
  sourceCount <> 1 or productCount <> 1 or /* other checks */

插入好的记录。对检查使用相同的查询，但添加额外的子查询以获取正确的产品ID和源ID。

insert into tbl_destination(sdate,source_id,product_id,amount, ...)
select
  sdate,
  source_id,
  product_id,
  amount,
  ...
from
(
    SELECT 
      MAX(t.s_id) as s_id,
      t.sdate,t.stype,t.snumber,t.code,
      SUM(t.amount) as amount, 

      (SELECT count(*) 
      FROM mapping m, source d 
      WHERE 
        TO_NUMBER(m.stage)=rec.snumber AND 
        m.month=EXTRACT(MONTH FROM rec.sdate) AND 
        m.year=EXTRACT(YEAR FROM rec.sdate) AND m.desc=d.source_desc AND
        m.month=d.month AND m.year=d.year AND m.name='SOURCE') as sourceCount,
      (SELECT min(source_id) 
      FROM mapping m, source d 
      WHERE 
        TO_NUMBER(m.stage)=rec.snumber AND 
        m.month=EXTRACT(MONTH FROM rec.sdate) AND 
        m.year=EXTRACT(YEAR FROM rec.sdate) AND m.desc=d.source_desc AND
        m.month=d.month AND m.year=d.year AND m.name='SOURCE') as source_id,

      (SELECT count(*)
      FROM mapping m, product p
      WHERE 
        m.stage=rec.code AND 
        m.month=EXTRACT(MONTH FROM rec.sdate) AND 
        m.year=EXTRACT(YEAR FROM rec.sdate) AND 
        m.desc=p.product_name AND m.month=p.month AND 
        m.year=p.year AND m.name='PRODUCT') as productCount,
      (SELECT min(product_id)
      FROM mapping m, product p
      WHERE 
        m.stage=rec.code AND 
        m.month=EXTRACT(MONTH FROM rec.sdate) AND 
        m.year=EXTRACT(YEAR FROM rec.sdate) AND 
        m.desc=p.product_name AND m.month=p.month AND 
        m.year=p.year AND m.name='PRODUCT') as product_id,

      /* other checks */        

    FROM 
      stable t 
    WHERE 
      t.sdate=p_date AND t.stype=p_type 
      AND t.snumber=p_num 
    GROUP BY 
      t.sdate, t.snumber, t.stype
) x
having 
  sourceCount = 1 and productCount = 1 and /* other checks */

Answer 2

通常最高效的方法是将plsql转换为基于集合的操作，并摆脱LOOP，我将首先采用驱动查询并将其嵌入到每个查询中（在循环中）。然后将它们变成插入物。注意将IF语句中的任何逻辑合并到WHERE子句中。

e.g：当您在没有找到记录的情况下插入错误时，可以将第一个SELECT INTO .... EXCEPTION块更改为直接插入，其中无法在映射表中找到任何行

    INSERT INTO tbl_errors
    SELECT s_id, 1 as e_id , 'source_id' as reason 
    FROM
    (
        SELECT MAX(t.s_id) as s_id,t.sdate,t.stype,t.snumber,t.code,
                   SUM(t.amount) as amount, t... (other fields)
        FROM stable t 
        WHERE t.sdate=p_date AND t.stype=p_type AND t.snumber=p_num 
        GROUP BY t.sdate,t.snumber,t.stype, t... (other fields)
    ) drv
    LEFT JOIN mapping m ON TO_NUMBER(m.stage) = drv.s_id   --etc 
    LEFT JOIN source d ON m.desc=d.source_desc AND m.month=d.month --etc
    WHERE m.stage IS NULL

最终你会得到几个插入，现在应该可以优化furthur并将所有选择合并到一个语句中并将操作作为单个插入执行。

然后插入错误只需插入驱动查询中没有错误的行

即：

INSERT INTO tbl_destination
SELECT * from drv
WHERE NOT EXISTS(SELECT * from tbl_errors WHERE s_id=drv.s_id)

建议如何优化解决方案（所有记录的LOOP并检查错误）

2 个答案: