Details
-
Improvement
-
Status: Resolved
-
Minor
-
Resolution: Incomplete
-
2.3.0
-
None
Description
After column rename projection, the ProjectExec's outputOrdering and outputPartitioning should reflect the projected columns as well. For example,
SELECT b1
FROM (
SELECT a a1, b b1
FROM testData2
ORDER BY a
)
ORDER BY a1
The inner query is ordered on a1 as well. If we had a rule to eliminate Sort on sorted result, together with this fix, the order-by in the outer query could have been optimized out.
Similarly, the below query
SELECT *
FROM (
SELECT t1.a a1, t2.a a2, t1.b b1, t2.b b2
FROM testData2 t1
LEFT JOIN testData2 t2
ON t1.a = t2.a
)
JOIN testData2 t3
ON a1 = t3.a
is equivalent to
SELECT * FROM testData2 t1 LEFT JOIN testData2 t2 ON t1.a = t2.a JOIN testData2 t3 ON t1.a = t3.a
, so the unnecessary sorting and hash-partitioning that have been optimized out for the second query should have be eliminated in the first query as well.
