[SPARK-50781][SQL] Cache QueryPlan.expressions

### What changes were proposed in this pull request? Cache `QueryPlan.expressions` ### Why are the changes needed? We observed that we were spending a significant amount of time recomputing. ### Does this PR introduce _any_ user-facing change? No ### How was this patch tested? Existing Tests ### Was this patch authored or co-authored using generative AI tooling? No Closes apache#49435 from zhengruifeng/sql_cache_expressions. Authored-by: Ruifeng Zheng <[email protected]> Signed-off-by: Ruifeng Zheng <[email protected]>
panbingkun · Jan 10, 2025 · 7845867 · 7845867
1 parent 868549e
commit 7845867
Showing 1 changed file with 4 additions and 2 deletions.
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/QueryPlan.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/QueryPlan.scala
@@ -283,7 +283,9 @@ abstract class QueryPlan[PlanType <: QueryPlan[PlanType]]
   }
 
   /** Returns all of the expressions present in this query plan operator. */
-  final def expressions: Seq[Expression] = {
+  final def expressions: Seq[Expression] = _expressions()
+
+  private val _expressions = new BestEffortLazyVal[Seq[Expression]](() => {
     // Recursively find all expressions from a traversable.
     def seqToExpressions(seq: Iterable[Any]): Iterable[Expression] = seq.flatMap {
       case e: Expression => e :: Nil
@@ -297,7 +299,7 @@ abstract class QueryPlan[PlanType <: QueryPlan[PlanType]]
       case seq: Iterable[_] => seqToExpressions(seq)
       case other => Nil
     }.toSeq
-  }
+  })
 
   /**
    * A variant of `transformUp`, which takes care of the case that the rule replaces a plan node