cloud-fan commented on a change in pull request #32559:
URL: https://github.com/apache/spark/pull/32559#discussion_r633589143
##########
File path:
sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/SubexpressionEliminationSuite.scala
##########
@@ -309,6 +309,22 @@ class SubexpressionEliminationSuite extends SparkFunSuite
with ExpressionEvalHel
CodeGenerator.compile(code)
}
}
+
+ test("SPARK-35410: SubExpr elimination should not include redundant child
exprs " +
+ "for conditional expressions") {
Review comment:
is this only a problem for conditional expression?
##########
File path:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/EquivalentExpressions.scala
##########
@@ -82,21 +82,31 @@ class EquivalentExpressions {
/**
* Adds only expressions which are common in each of given expressions, in a
recursive way.
* For example, given two expressions `(a + (b + (c + 1)))` and `(d + (e +
(c + 1)))`,
- * the common expression `(c + 1)` will be added into `equivalenceMap`.
+ * the common expression `(c + 1)` will be added into `equivalenceMap`. Note
that if an
+ * expression and its child expressions are all commonly occurred in each of
given expressions,
+ * we filter out the child expressions. For example, if `((a + b) + c)` and
`(a + b)` are
+ * common expressions, we only add `((a + b) + c)`.
*/
private def addCommonExprs(
exprs: Seq[Expression],
addFunc: Expression => Boolean = addExpr): Unit = {
val exprSetForAll = mutable.Set[Expr]()
addExprTree(exprs.head, addExprToSet(_, exprSetForAll))
- val commonExprSet = exprs.tail.foldLeft(exprSetForAll) { (exprSet, expr) =>
+ val candidateExprs = exprs.tail.foldLeft(exprSetForAll) { (exprSet, expr)
=>
val otherExprSet = mutable.Set[Expr]()
addExprTree(expr, addExprToSet(_, otherExprSet))
exprSet.intersect(otherExprSet)
}
- commonExprSet.foreach(expr => addFunc(expr.e))
+ // Not all expressions in the set should be added. We should filter out
the subexprs.
+ val commonExprSet = candidateExprs.filter { candidateExpr =>
+ candidateExprs.forall { expr =>
+ expr == candidateExpr ||
expr.e.find(_.semanticEquals(candidateExpr.e)).isEmpty
+ }
Review comment:
+1, but I don't have a better idea now...
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