Liya Fan created CALCITE-4241:
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Summary: Some improvements to metadata query
Key: CALCITE-4241
URL: https://issues.apache.org/jira/browse/CALCITE-4241
Project: Calcite
Issue Type: Improvement
Components: core
Reporter: Liya Fan
Assignee: Liya Fan
# For RelMdColumnUniqueness#areColumnsUnique(RelSubset, RelMetadataQuery,
ImmutableBitSet, boolean), we can return early as we encounter the first null.
# For RelMdDistinctRowCount#getDistinctRowCount(Values, RelMetadataQuery,
ImmutableBitSet, RexNode), we can get the distinct row count accurately,
instead of guessing that half of the elements are distinct.
# In class RelMdUtil, areColumnsDefinitelyUnique and
areColumnsDefinitelyUniqueWhenNullsFiltered have identical behaviors, so we
should use the formmer, which is more efficient.
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