KyleLi1985 commented on a change in pull request #23271: [SPARK-26318][SQL]
Enhance function merge performance in Row
URL: https://github.com/apache/spark/pull/23271#discussion_r240491672
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File path: sql/catalyst/src/main/scala/org/apache/spark/sql/Row.scala
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@@ -58,8 +58,21 @@ object Row {
* Merge multiple rows into a single row, one after another.
*/
def merge(rows: Row*): Row = {
- // TODO: Improve the performance of this if used in performance critical
part.
- new GenericRow(rows.flatMap(_.toSeq).toArray)
+ val size = rows.size
+ var number = 0
+ for (i <- 0 until size) {
+ number = number + rows(i).size
+ }
+ val container = Array.ofDim[Any](number)
+ var n = 0
+ for (i <- 0 until size) {
Review comment:
Only primitively use size, subSize, and number information and control the
container will improve the performance more.
up to
call 100000000 time Row.merge(row1) need 18064 millisecond
call 100000000 time Row.merge(rows:_*) need 25651 millisecond
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