gengliangwang opened a new pull request #28733:
URL: https://github.com/apache/spark/pull/28733


   ### What changes were proposed in this pull request?
   
   This PR add a new rule to support push predicate through join by rewriting 
join condition to CNF(conjunctive normal form). The following example is the 
steps of this rule:
   
   1. Prepare Table:
   
   ```sql
   CREATE TABLE x AS SELECT * FROM (VALUES (1, 2, 3, 4)) AS x(a, b, c, d);
   CREATE TABLE y AS SELECT * FROM (VALUES (1, 2, 3, 4)) AS x(a, b, c, d);
   EXPLAIN SELECT x.* FROM x JOIN y ON ((x.a > 1 AND x.a < 3 AND y.b = 1) OR 
(x.a > 3 AND x.a < 5 AND y.b = 2));
   ```
   
   2. Convert the join condition to CNF:
   
   Step | Current condition
   --- | ---
   init | (x.a > 1 AND x.a < 3 AND y.b = 1) OR (x.a > 3 AND x.a < 5 AND y.b = 2)
   step 1 | ((x.a > 1 AND x.a < 3) OR (x.a > 3 AND x.a < 5 AND y.b = 2)) AND 
((y.b = 1) OR (x.a > 3 AND x.a < 5 AND y.b = 2))
   step 2 | ((x.a > 1 AND x.a < 3) OR (x.a > 3 AND x.a < 5)) AND ((x.a > 1 AND 
x.a < 3) OR (y.b = 2)) AND ((y.b = 1) OR (x.a > 3 AND x.a < 5 AND y.b = 2))
   step 3 | ((x.a > 1 AND x.a < 3) OR (x.a > 3 AND x.a < 5)) AND ((x.a > 1 AND 
x.a < 3) OR (y.b = 2)) AND ((y.b = 1) OR (x.a > 3 AND x.a < 5)) AND ((y.b = 1) 
OR (y.b = 2))
   
   3. Split conjunctive predicates
   
   Predicates
   ---|
   ((x.a > 1 AND x.a < 3) OR (x.a > 3 AND x.a < 5))
   ((x.a > 1 AND x.a < 3) OR (y.b = 2))
   ((y.b = 1) OR (x.a > 3 AND x.a < 5))
   ((y.b = 1) OR (y.b = 2))
   
   4. Push predicate
   
   Table | Predicate
   --- | ---
   x | ((x.a > 1 AND x.a < 3) OR (x.a > 3 AND x.a < 5))
   y | ((y.b = 1) OR (y.b = 2))
   
   
   
   ### Why are the changes needed?
   Improve query performance. PostgreSQL, 
[Impala](https://issues.apache.org/jira/browse/IMPALA-9183) and Hive support 
this feature.
   
   
   ### Does this PR introduce _any_ user-facing change?
   No.
   
   
   ### How was this patch tested?
   Unit test and benchmark test.
   
   
   SQL | Before this PR | After this PR
   --- | --- | ---
   TPCDS 5T Q13 | 84s | 21s
   TPCDS 5T q85 | 66s | 34s
   TPCH 1T q19 | 37s | 32s
   
   


----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

For queries about this service, please contact Infrastructure at:
[email protected]



---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]

Reply via email to