/**
* Infers predicates for an Aggregate.
*
* <p>Pulls up predicates that only contains references to columns in the GroupSet. For e.g.
*
* <pre>
* childPullUpExprs : { a > 7, b + c < 10, a + e = 9}
* groupSet : { a, b}
* pulledUpExprs : { a > 7}
* </pre>
*/
public RelOptPredicateList getPredicates(Aggregate agg) {
RelNode child = agg.getInput();
RelOptPredicateList childInfo = RelMetadataQuery.getPulledUpPredicates(child);
List<RexNode> aggPullUpPredicates = new ArrayList<RexNode>();
ImmutableBitSet groupKeys = agg.getGroupSet();
Mapping m =
Mappings.create(
MappingType.PARTIAL_FUNCTION,
child.getRowType().getFieldCount(),
agg.getRowType().getFieldCount());
int i = 0;
for (int j : groupKeys) {
m.set(j, i++);
}
for (RexNode r : childInfo.pulledUpPredicates) {
ImmutableBitSet rCols = RelOptUtil.InputFinder.bits(r);
if (groupKeys.contains(rCols)) {
r = r.accept(new RexPermuteInputsShuttle(m, child));
aggPullUpPredicates.add(r);
}
}
return RelOptPredicateList.of(aggPullUpPredicates);
}
/**
* Infers predicates for a project.
*
* <ol>
* <li>create a mapping from input to projection. Map only positions that directly reference an
* input column.
* <li>Expressions that only contain above columns are retained in the Project's pullExpressions
* list.
* <li>For e.g. expression 'a + e = 9' below will not be pulled up because 'e' is not in the
* projection list.
* <pre>
* childPullUpExprs: {a > 7, b + c < 10, a + e = 9}
* projectionExprs: {a, b, c, e / 2}
* projectionPullupExprs: {a > 7, b + c < 10}
* </pre>
* </ol>
*/
public RelOptPredicateList getPredicates(Project project) {
RelNode child = project.getInput();
final RexBuilder rexBuilder = project.getCluster().getRexBuilder();
RelOptPredicateList childInfo = RelMetadataQuery.getPulledUpPredicates(child);
List<RexNode> projectPullUpPredicates = new ArrayList<RexNode>();
ImmutableBitSet.Builder columnsMappedBuilder = ImmutableBitSet.builder();
Mapping m =
Mappings.create(
MappingType.PARTIAL_FUNCTION,
child.getRowType().getFieldCount(),
project.getRowType().getFieldCount());
for (Ord<RexNode> o : Ord.zip(project.getProjects())) {
if (o.e instanceof RexInputRef) {
int sIdx = ((RexInputRef) o.e).getIndex();
m.set(sIdx, o.i);
columnsMappedBuilder.set(sIdx);
}
}
// Go over childPullUpPredicates. If a predicate only contains columns in
// 'columnsMapped' construct a new predicate based on mapping.
final ImmutableBitSet columnsMapped = columnsMappedBuilder.build();
for (RexNode r : childInfo.pulledUpPredicates) {
ImmutableBitSet rCols = RelOptUtil.InputFinder.bits(r);
if (columnsMapped.contains(rCols)) {
r = r.accept(new RexPermuteInputsShuttle(m, child));
projectPullUpPredicates.add(r);
}
}
// Project can also generate constants. We need to include them.
for (Ord<RexNode> expr : Ord.zip(project.getProjects())) {
if (RexLiteral.isNullLiteral(expr.e)) {
projectPullUpPredicates.add(
rexBuilder.makeCall(
SqlStdOperatorTable.IS_NULL, rexBuilder.makeInputRef(project, expr.i)));
} else if (RexUtil.isConstant(expr.e)) {
final List<RexNode> args =
ImmutableList.of(rexBuilder.makeInputRef(project, expr.i), expr.e);
final SqlOperator op =
args.get(0).getType().isNullable() || args.get(1).getType().isNullable()
? SqlStdOperatorTable.IS_NOT_DISTINCT_FROM
: SqlStdOperatorTable.EQUALS;
projectPullUpPredicates.add(rexBuilder.makeCall(op, args));
}
}
return RelOptPredicateList.of(projectPullUpPredicates);
}
private void computeNextMapping(int level) {
int t = columnSets[level].nextSetBit(iterationIdx[level]);
if (t < 0) {
if (level == 0) {
nextMapping = null;
} else {
iterationIdx[level] = 0;
computeNextMapping(level - 1);
}
} else {
nextMapping.set(columns[level], t);
iterationIdx[level] = t + 1;
}
}
private void initializeMapping() {
nextMapping =
Mappings.create(
MappingType.PARTIAL_FUNCTION,
nSysFields + nFieldsLeft + nFieldsRight,
nSysFields + nFieldsLeft + nFieldsRight);
for (int i = 0; i < columnSets.length; i++) {
BitSet c = columnSets[i];
int t = c.nextSetBit(iterationIdx[i]);
if (t < 0) {
nextMapping = null;
return;
}
nextMapping.set(columns[i], t);
iterationIdx[i] = t + 1;
}
}
/**
* 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);
}
