liyafan82 commented on a change in pull request #2154:
URL: https://github.com/apache/calcite/pull/2154#discussion_r490725620
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File path:
core/src/main/java/org/apache/calcite/rel/metadata/RelMdDistinctRowCount.java
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@@ -79,6 +82,37 @@ public Double getDistinctRowCount(RelNode rel,
RelMetadataQuery mq,
return null;
}
+ public Double getDistinctRowCount(TableScan rel, RelMetadataQuery mq,
+ ImmutableBitSet groupKey, RexNode predicate) {
+ final double selectivity = predicate == null ? 1D : mq.getSelectivity(rel,
predicate);
+ final boolean uniq = RelMdUtil.areColumnsDefinitelyUnique(mq, rel,
groupKey);
+ if (uniq) {
+ return NumberUtil.multiply(mq.getRowCount(rel), selectivity);
Review comment:
If the column values are unique, shouldn't we return 1 * selectivity?
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