rubenada commented on code in PR #4556:
URL: https://github.com/apache/calcite/pull/4556#discussion_r2394211999
##########
core/src/main/java/org/apache/calcite/rel/metadata/RelMdColumnUniqueness.java:
##########
@@ -334,45 +334,56 @@ public Boolean areColumnsUnique(Intersect rel,
RelMetadataQuery mq,
}
// If the original column mask contains columns from both the left and
- // right hand side, then the columns are unique if and only if they're
+ // right hand side, then the columns are unique if (but not only if)
they're
// unique for their respective join inputs
Boolean leftUnique = mq.areColumnsUnique(left, leftColumns, ignoreNulls);
Boolean rightUnique = mq.areColumnsUnique(right, rightColumns,
ignoreNulls);
if ((leftColumns.cardinality() > 0)
&& (rightColumns.cardinality() > 0)) {
if ((leftUnique == null) || (rightUnique == null)) {
return null;
- } else {
- return leftUnique && rightUnique;
+ } else if (leftUnique && rightUnique) {
+ return true;
}
}
- // If we're only trying to determine uniqueness for columns that
- // originate from one join input, then determine if the equijoin
- // columns from the other join input are unique. If they are, then
- // the columns are unique for the entire join if they're unique for
- // the corresponding join input, provided that input is not null
- // generating.
+ // Determine if the equijoin columns from the other join input are unique.
+ // If they are, then the columns are unique for the entire join if they're
unique for
+ // the corresponding join input, provided that input is not null
generating.
if (leftColumns.cardinality() > 0) {
if (rel.getJoinType().generatesNullsOnLeft()) {
return false;
}
- Boolean rightJoinColsUnique =
- mq.areColumnsUnique(right, joinInfo.rightSet(), ignoreNulls);
- if ((rightJoinColsUnique == null) || (leftUnique == null)) {
+ if (leftUnique == null) {
return null;
}
- return rightJoinColsUnique && leftUnique;
- } else if (rightColumns.cardinality() > 0) {
+ if (leftUnique) {
+ Boolean joinRightKeyUnique = mq.areColumnsUnique(right,
joinInfo.rightSet(), ignoreNulls);
+ if (joinRightKeyUnique == null) {
+ return null;
+ }
+ if (joinRightKeyUnique) {
+ return true;
+ }
+ }
+ }
+ // Similarly, if the columns originate from the right input
+ if (rightColumns.cardinality() > 0) {
if (rel.getJoinType().generatesNullsOnRight()) {
return false;
}
- Boolean leftJoinColsUnique =
- mq.areColumnsUnique(left, joinInfo.leftSet(), ignoreNulls);
- if ((leftJoinColsUnique == null) || (rightUnique == null)) {
+ if (rightUnique == null) {
return null;
}
- return leftJoinColsUnique && rightUnique;
+ if (rightUnique) {
+ Boolean joinRightKeyUnique = mq.areColumnsUnique(left,
joinInfo.leftSet(), ignoreNulls);
Review Comment:
done
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