Github user concretevitamin commented on a diff in the pull request:
https://github.com/apache/spark/pull/1238#discussion_r14738387
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/LogicalPlan.scala
---
@@ -26,6 +26,17 @@ import org.apache.spark.sql.catalyst.trees
abstract class LogicalPlan extends QueryPlan[LogicalPlan] {
self: Product =>
+ protected class Estimates {
+ lazy val childrenEstimations = children.map(_.estimates)
+ lazy val cardinality: Long = childrenEstimations.map(_.cardinality).sum
+ lazy val sizeInBytes: Long = childrenEstimations.map(_.sizeInBytes).sum
--- End diff --
@chenghao-intel Yes, `cardinality` (now renamed to `numTuples`) is not used
in this PR and any optimizations utilizing it are intended for future work.
@marmbrus I don't understand the argument of using 1 for cardinality
(numTuples) here? It seems to me in either an inner join or an outer join, if
one side has numTuples equal to 0, the summation still provides a correct
overestimate. Additionally, numTuples is not used in this patch.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
