Github user beyond1920 commented on a diff in the pull request:
https://github.com/apache/flink/pull/3058#discussion_r95967156
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/plan/nodes/dataset/DataSetSort.scala
---
@@ -71,6 +72,21 @@ class DataSetSort(
)
}
+ override def estimateRowCount(metadata: RelMetadataQuery): Double = {
+ val inputRowCnt = metadata.getRowCount(this.getInput)
+ if (inputRowCnt == null) {
+ inputRowCnt
+ } else {
+ val rowCount = Math.max(inputRowCnt - limitStart, 0D)
--- End diff --
Hmm, the estimation 0 only happens if inputRowCount <= start and (fetch
is null or fetchValue<=0). I think this estimation is reasonable in this case.
Besides, why choose return 1 instead of 0.1 or 0.01 or other values?
---
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.
---
