Alex Antonov created SPARK-13940:
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Summary: Predicate Transitive Closure Transformation
Key: SPARK-13940
URL: https://issues.apache.org/jira/browse/SPARK-13940
Project: Spark
Issue Type: Improvement
Components: Optimizer
Affects Versions: 1.6.0
Reporter: Alex Antonov
A relatively simple transformation is missing from Catalyst's arsenal -
generation of transitive predicates. For instance, if you have got the
following query:
{code}
select *
from table1 t1
join table2 t2
on t1.a = t2.b
where t1.a = 42
{code}
then it is a fair assumption that t2.b also equals 42 hence an additional
predicate could be generated. The additional predicate could in turn be pushed
down through the join and improve performance of the whole query by filtering
out the data before joining it.
Such an transformation exists in Oracle DB and called transitive closure which
hopefully should explain the title of this Jira
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