/** Variant of {@link #trimFields(RelNode, BitSet, Set)} for {@link SortRel}. */
public TrimResult trimFields(SortRel sort, BitSet fieldsUsed, Set<RelDataTypeField> extraFields) {
final RelDataType rowType = sort.getRowType();
final int fieldCount = rowType.getFieldCount();
final RelCollation collation = sort.getCollation();
final RelNode input = sort.getChild();
// We use the fields used by the consumer, plus any fields used as sort
// keys.
BitSet inputFieldsUsed = (BitSet) fieldsUsed.clone();
for (RelFieldCollation field : collation.getFieldCollations()) {
inputFieldsUsed.set(field.getFieldIndex());
}
// Create input with trimmed columns.
final Set<RelDataTypeField> inputExtraFields = Collections.emptySet();
TrimResult trimResult = trimChild(sort, input, inputFieldsUsed, inputExtraFields);
RelNode newInput = trimResult.left;
final Mapping inputMapping = trimResult.right;
// If the input is unchanged, and we need to project all columns,
// there's nothing we can do.
if (newInput == input && inputMapping.isIdentity() && fieldsUsed.cardinality() == fieldCount) {
return new TrimResult(sort, Mappings.createIdentity(fieldCount));
}
final SortRel newSort =
sort.copy(sort.getTraitSet(), newInput, RexUtil.apply(inputMapping, collation));
assert newSort.getClass() == sort.getClass();
// The result has the same mapping as the input gave us. Sometimes we
// return fields that the consumer didn't ask for, because the filter
// needs them for its condition.
return new TrimResult(newSort, inputMapping);
}
public Boolean areColumnsUnique(SortRel rel, BitSet columns, boolean ignoreNulls) {
return RelMetadataQuery.areColumnsUnique(rel.getChild(), columns, ignoreNulls);
}
