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:
Currently 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.
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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