加入性能较差的SQL查询

Question

我在为Oracle 12c编写的查询中遇到性能很差的问题。这可能与我对连接的低效使用有关，并希望有人能帮我解决我出错的地方。我的查询目前有需要一分钟时间才能运行。

我正在尝试在表和列名返回：

• 列属于主键
• 列类型是数字
• 表的所有者是MY_OWNER
• 的主键是一列约束

真正水流我的查询看起来如下

SELECT consCols.table_name, consCols.column_name 
FROM all_cons_columns consCols 
INNER JOIN all_constraints cons 
    ON cons.constraint_name = consCols.constraint_name 
INNER JOIN all_tab_columns cols 
    ON consCols.table_name = cols.table_name AND consCols.column_name = cols.column_name 
WHERE cons.constraint_type = 'P' 
AND cons.owner = 'MY_OWNER' 
AND cols.data_type = 'NUMBER' 
AND consCols.table_name IN(
    SELECT consCols2.table_name 
    FROM all_cons_columns consCols2 
    INNER JOIN all_constraints cons2 
    ON cons2.constraint_name = consCols2.constraint_name 
    WHERE cons2.constraint_type = 'P' 
    AND cons2.owner = 'MY_OWNER' 
    GROUP BY consCols2.table_name 
    HAVING COUNT(consCols2.table_name) = 1 
); 

谢谢你给我的任何帮助。

Answer 1

将使用分析函数加快查询？

SELECT table_name, column_name 
FROM (SELECT consCols.table_name, consCols.column_name, cols.data_type, 
      COUNT(*) OVER (PARTITION BY consCols.table_name) as cnt 
     FROM all_cons_columns consCols INNER JOIN 
      all_constraints cons 
      ON cons.constraint_name = consCols.constraint_name INNER JOIN 
      all_tab_columns cols 
      ON consCols.table_name = cols.table_name AND consCols.column_name = cols.column_name 
     WHERE cons.constraint_type = 'P' AND 
      cons.owner = 'MY_OWNER' 
    ) tc    
WHERE data_type = 'NUMBER' AND cnt = 1; 

甚至聚合？

SELECT consCols.table_name, consCols.column_name 
    FROM all_cons_columns consCols INNER JOIN 
     all_constraints cons 
     ON cons.constraint_name = consCols.constraint_name INNER JOIN 
     all_tab_columns cols 
     ON consCols.table_name = cols.table_name AND consCols.column_name = cols.column_name 
    WHERE cons.constraint_type = 'P' AND 
     cons.owner = 'MY_OWNER' 
    GROUP BY consCols.table_name, consCols.column_name 
    HAVING COUNT(*) = 1 AND 
     MAX(cols.data_type) = 'NUMBER'; 

这是第三个选项：

SELECT consCols.table_name, consCols.column_name 
    FROM all_cons_columns consCols INNER JOIN 
     all_constraints cons 
     ON cons.constraint_name = consCols.constraint_name INNER JOIN 
     all_tab_columns cols 
     ON consCols.table_name = cols.table_name AND consCols.column_name = cols.column_name 
    WHERE cons.constraint_type = 'P' AND 
     cons.owner = 'MY_OWNER' AND 
     cols.data_type = 'NUMBER' AND 
     NOT EXISTS (SELECT 1 
        FROM all_cons_columns acc 
        WHERE acc.constraint_name = consCols.constraint_name AND 
          acc.table_name = consCols.table_name AND 
          acc.column_name <> consCols.column_name 
        ); 

这消除了汇总和查询应该是比较快的。