Skip to content

[SPARK-18111] [SQL] Wrong ApproximatePercentile answer when multiple records have the minimum value #15641

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
wzhfy wants to merge 4 commits into from
Closed

[SPARK-18111] [SQL] Wrong ApproximatePercentile answer when multiple records have the minimum value #15641

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
26a4f85
keep the min element when merge
Oct 26, 2016
3ad5920
typo
Oct 26, 2016
de1fdd5
don't add the minimum element if has only one element
Oct 26, 2016
0a5489c
use a more obvious example
Oct 27, 2016
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 3 additions & 1 deletion sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/QuantileSummaries.scala
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -264,7 +264,9 @@ object QuantileSummaries {
res.prepend(head)
// If necessary, add the minimum element:
val currHead = currentSamples.head
if (currHead.value < head.value) {
// don't add the minimum element if `currentSamples` has only one element (both `currHead` and
// `head` point to the same element)
if (currHead.value <= head.value && currentSamples.length > 1) {
res.prepend(currentSamples.head)
}
res.toArray
Expand Down
11 changes: 11 additions & 0 deletions sql/core/src/test/scala/org/apache/spark/sql/ApproximatePercentileQuerySuite.scala
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -64,6 +64,17 @@ class ApproximatePercentileQuerySuite extends QueryTest with SharedSQLContext {
}
}

test("percentile_approx, multiple records with the minimum value in a partition") {
withTempView(table) {
spark.sparkContext.makeRDD(Seq(1, 1, 2, 1, 1, 3, 1, 1, 4, 1, 1, 5), 4).toDF("col")
.createOrReplaceTempView(table)
checkAnswer(
spark.sql(s"SELECT percentile_approx(col, array(0.5)) FROM $table"),
Row(Seq(1.0D))
)
}
}

test("percentile_approx, with different accuracies") {

withTempView(table) {
Expand Down