我在为Oracle 12c编写的查询中遇到了非常糟糕的性能。 这可能与我对连接的低效使用有关,并且希望有人可以帮我解决我出错的地方。 我的查询目前需要一分钟才能运行 。
我正在尝试返回表和列名称:
该列属于主键 列类型为Number 表的所有者是MY_OWNER 主键是单列约束目前我的查询如下所示
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 );感谢您给我的任何帮助。
I'm experiencing very poor performance in a query I've written for Oracle 12c. It's probably related to my inefficient use of joins and was hoping someone could help me out with where I'm going wrong. The query I have is currently taking over a minute to run.
I'm am trying to return the table and column names where:
The column belongs to a Primary Key The column type is Number The owner of the table is MY_OWNER The Primary Key is a single column constraintCurrently my query looks as follows
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 );Thank you for any help you can give me.
最满意答案
使用分析函数会加快查询速度吗?
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';这是第三种选择:
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 );这消除了聚合,查找应该相对较快。
Would using analytic functions speed the query?
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;Or even aggregation?
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';Here is a third option:
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 );This eliminates the aggregation and the lookup should be relatively fast.
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