Query the database;

Question

Hello;
My application is running the following query:
SELECT NULL AS pktable_cat,
      p.owner as pktable_schem,
      p.table_name as pktable_name,
      pc.column_name as pkcolumn_name,
      NULL as fktable_cat,
      f.owner as fktable_schem,
      f.table_name as fktable_name,
      fc.column_name as fkcolumn_name,
      fc.position as key_seq,
      NULL as update_rule,
      decode (f.delete_rule, 'CASCADE', 0, 'SET NULL', 2, 1) as delete_rule,
      f.constraint_name as fk_name,
      p.constraint_name as pk_name,
      decode(f.deferrable, 'DEFERRABLE',5 ,'NOT DEFERRABLE',7 , 'DEFERRED', 6 ) deferrability
FROM all_cons_columns pc,
      all_constraints p,
      all_cons_columns fc,
      all_constraints f
WHERE 1 = 1 AND
      p.table_name = '?' /*Bind1*/ AND
      p.owner = '?' /*Bind2*/ AND
      f.constraint_type = 'R' AND
      p.owner = f.r_owner AND
      p.constraint_name = f.r_constraint_name AND
      p.constraint_type = 'P' AND
      pc.owner = p.owner AND
      pc.constraint_name = p.constraint_name AND
      pc.table_name = p.table_name AND
      fc.owner = f.owner AND
      fc.constraint_name = f.constraint_name AND
      fc.table_name = f.table_name AND
      fc.position = pc.position
ORDER BY fktable_schem, fktable_name, key_seq
We use the CF9 and the database is ORACLE 11G.
The same is performed several times a day and it's hurting the performance of queries in my system. How to fix it, or remove from the application;
It is executed by the same driver ?
thanks;
Jaider Fraga;

Answer 1

Hello
As Mr Dan mentioned, you can do move the condition mentioned in 'where' clause to Join statements .Something like below
SELECT NULL AS pktable_cat,
      p.owner as pktable_schem,
      p.table_name as pktable_name,
      pc.column_name as pkcolumn_name,
      NULL as fktable_cat,
      f.owner as fktable_schem,
      f.table_name as fktable_name,
      fc.column_name as fkcolumn_name,
      fc.position as key_seq,
      NULL as update_rule,
      decode (f.delete_rule, 'CASCADE', 0, 'SET NULL', 2, 1) as delete_rule,
      f.constraint_name as fk_name,
      p.constraint_name as pk_name,
      decode(f.deferrable, 'DEFERRABLE',5 ,'NOT DEFERRABLE',7 , 'DEFERRED', 6 ) deferrability
FROM all_cons_columns pc ,
      INNER JOIN all_constraints p ON
               p.table_name = '?' /*Bind1*/ AND
               p.owner = '?' /*Bind2*/ AND,
               p.constraint_type = 'P' AND,
               pc.owner = p.owner AND,
               pc.constraint_name = p.constraint_name AND,
               pc.table_name = p.table_name
      INNER JOIN all_cons_columns fc ON
               fc.position = pc.position
      INNER JOIN all_constraints f
               f.constraint_type = 'R' AND
               p.owner = f.r_owner AND
               p.constraint_name = f.r_constraint_name AND
               fc.owner = f.owner AND
               fc.constraint_name = f.constraint_name AND
               fc.table_name = f.table_name
WHERE 1 = 1
ORDER BY fktable_schem, fktable_name, key_seq
Advantage is that if you are using the conditions in join statement the query results are filtered on joinning tables itself rather than taking the whole data and gets filtered by where clause. This will improve the query performance and the results will also be correct ones
Hope this help
Regards
Sreekar