szehon-ho commented on code in PR #58666:
URL: https://github.com/apache/spark/pull/58666#discussion_r3974672965
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sql/catalyst/src/main/scala/org/apache/spark/sql/execution/datasources/v2/DataSourceV2Relation.scala:
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@@ -602,11 +609,16 @@ object DataSourceV2Relation {
val catalystColStat = ColumnStat(distinct, min, max, nullCount,
avgLen, maxLen, histogram)
- output.foreach(attribute => {
- if (attribute.name.equals(key.describe())) {
- colStats = colStats :+ (attribute -> catalystColStat)
- }
- })
+ // Only single-part references can name a top-level output attribute;
nested references
+ // (fieldNames.length > 1) have no place in the attribute-keyed
catalyst statistics.
+ val fieldNames = key.fieldNames
+ if (fieldNames.length == 1) {
+ output.foreach(attribute => {
+ if (resolver(attribute.name, fieldNames.head)) {
Review Comment:
Could this avoid attaching one statistic to every resolver match? In
case-insensitive mode, an output containing both `id` and `ID` makes either key
match both attributes, potentially giving CBO incorrect statistics. Could we
accept only a unique match, perhaps preferring an exact raw-name match, and add
a test for case-conflicting outputs?
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