/**
* Variant of {@link #trimFields(RelNode, ImmutableBitSet, Set)} for {@link
* org.apache.hadoop.hive.ql.optimizer.calcite.reloperators.HiveMultiJoin}.
*/
public TrimResult trimFields(
HiveMultiJoin join, ImmutableBitSet fieldsUsed, Set<RelDataTypeField> extraFields) {
final int fieldCount = join.getRowType().getFieldCount();
final RexNode conditionExpr = join.getCondition();
// Add in fields used in the condition.
final Set<RelDataTypeField> combinedInputExtraFields =
new LinkedHashSet<RelDataTypeField>(extraFields);
RelOptUtil.InputFinder inputFinder = new RelOptUtil.InputFinder(combinedInputExtraFields);
inputFinder.inputBitSet.addAll(fieldsUsed);
conditionExpr.accept(inputFinder);
final ImmutableBitSet fieldsUsedPlus = inputFinder.inputBitSet.build();
int inputStartPos = 0;
int changeCount = 0;
int newFieldCount = 0;
List<RelNode> newInputs = new ArrayList<RelNode>();
List<Mapping> inputMappings = new ArrayList<Mapping>();
for (RelNode input : join.getInputs()) {
final RelDataType inputRowType = input.getRowType();
final int inputFieldCount = inputRowType.getFieldCount();
// Compute required mapping.
ImmutableBitSet.Builder inputFieldsUsed = ImmutableBitSet.builder();
for (int bit : fieldsUsedPlus) {
if (bit >= inputStartPos && bit < inputStartPos + inputFieldCount) {
inputFieldsUsed.set(bit - inputStartPos);
}
}
Set<RelDataTypeField> inputExtraFields = Collections.<RelDataTypeField>emptySet();
TrimResult trimResult = trimChild(join, input, inputFieldsUsed.build(), inputExtraFields);
newInputs.add(trimResult.left);
if (trimResult.left != input) {
++changeCount;
}
final Mapping inputMapping = trimResult.right;
inputMappings.add(inputMapping);
// Move offset to point to start of next input.
inputStartPos += inputFieldCount;
newFieldCount += inputMapping.getTargetCount();
}
Mapping mapping = Mappings.create(MappingType.INVERSE_SURJECTION, fieldCount, newFieldCount);
int offset = 0;
int newOffset = 0;
for (int i = 0; i < inputMappings.size(); i++) {
Mapping inputMapping = inputMappings.get(i);
for (IntPair pair : inputMapping) {
mapping.set(pair.source + offset, pair.target + newOffset);
}
offset += inputMapping.getSourceCount();
newOffset += inputMapping.getTargetCount();
}
if (changeCount == 0 && mapping.isIdentity()) {
return new TrimResult(join, Mappings.createIdentity(fieldCount));
}
// Build new join.
final RexVisitor<RexNode> shuttle =
new RexPermuteInputsShuttle(mapping, newInputs.toArray(new RelNode[newInputs.size()]));
RexNode newConditionExpr = conditionExpr.accept(shuttle);
final RelDataType newRowType =
RelOptUtil.permute(join.getCluster().getTypeFactory(), join.getRowType(), mapping);
final RelNode newJoin =
new HiveMultiJoin(
join.getCluster(),
newInputs,
newConditionExpr,
newRowType,
join.getJoinInputs(),
join.getJoinTypes(),
join.getJoinFilters());
return new TrimResult(newJoin, mapping);
}
