Github user clockfly commented on a diff in the pull request:
https://github.com/apache/spark/pull/14976#discussion_r77726882
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/QuantileSummaries.scala
---
@@ -59,9 +59,14 @@ class QuantileSummaries(
* @param x the new observation to insert into the summary
*/
def insert(x: Double): QuantileSummaries = {
- headSampled.append(x)
+ headSampled += x
if (headSampled.size >= defaultHeadSize) {
- this.withHeadBufferInserted
+ val result = this.withHeadBufferInserted
+ if (result.sampled.length >= compressThreshold) {
+ result.compress()
--- End diff --
@srowen
I think the compression decision need to be related with relative error
setting. (The smaller the relative error is, the less frequent we do
compression)
When implementing aggregation function percentile_approx, I have
implemented compression like this:
https://github.com/apache/spark/blob/master/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/aggregate/ApproximatePercentile.scala#L214
---
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 infrastruct...@apache.org or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org
For additional commands, e-mail: reviews-h...@spark.apache.org
