Exemple #1
0
  /** Variant of {@link #trimFields(RelNode, BitSet, Set)} for {@link JoinRel}. */
  public TrimResult trimFields(JoinRel join, BitSet fieldsUsed, Set<RelDataTypeField> extraFields) {
    final RelDataType rowType = join.getRowType();
    final int fieldCount = rowType.getFieldCount();
    final RexNode conditionExpr = join.getCondition();
    final int systemFieldCount = join.getSystemFieldList().size();

    // Add in fields used in the condition.
    BitSet fieldsUsedPlus = (BitSet) fieldsUsed.clone();
    final Set<RelDataTypeField> combinedInputExtraFields =
        new LinkedHashSet<RelDataTypeField>(extraFields);
    RelOptUtil.InputFinder inputFinder =
        new RelOptUtil.InputFinder(fieldsUsedPlus, combinedInputExtraFields);
    conditionExpr.accept(inputFinder);

    // If no system fields are used, we can remove them.
    int systemFieldUsedCount = 0;
    for (int i = 0; i < systemFieldCount; ++i) {
      if (fieldsUsed.get(i)) {
        ++systemFieldUsedCount;
      }
    }
    final int newSystemFieldCount;
    if (systemFieldUsedCount == 0) {
      newSystemFieldCount = 0;
    } else {
      newSystemFieldCount = systemFieldCount;
    }

    int offset = systemFieldCount;
    int changeCount = 0;
    int newFieldCount = newSystemFieldCount;
    List<RelNode> newInputs = new ArrayList<RelNode>(2);
    List<Mapping> inputMappings = new ArrayList<Mapping>();
    List<Integer> inputExtraFieldCounts = new ArrayList<Integer>();
    for (RelNode input : join.getInputs()) {
      final RelDataType inputRowType = input.getRowType();
      final int inputFieldCount = inputRowType.getFieldCount();

      // Compute required mapping.
      BitSet inputFieldsUsed = new BitSet(inputFieldCount);
      for (int bit : Util.toIter(fieldsUsedPlus)) {
        if (bit >= offset && bit < offset + inputFieldCount) {
          inputFieldsUsed.set(bit - offset);
        }
      }

      // If there are system fields, we automatically use the
      // corresponding field in each input.
      if (newSystemFieldCount > 0) {
        // calling with newSystemFieldCount == 0 should be safe but hits
        // http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6222207
        inputFieldsUsed.set(0, newSystemFieldCount);
      }

      // FIXME: We ought to collect extra fields for each input
      // individually. For now, we assume that just one input has
      // on-demand fields.
      Set<RelDataTypeField> inputExtraFields =
          input.getRowType().getField("_extra") == null
              ? Collections.<RelDataTypeField>emptySet()
              : combinedInputExtraFields;
      inputExtraFieldCounts.add(inputExtraFields.size());
      TrimResult trimResult = trimChild(join, input, inputFieldsUsed, 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.
      offset += inputFieldCount;
      newFieldCount += inputMapping.getTargetCount() + inputExtraFields.size();
    }

    Mapping mapping = Mappings.create(MappingType.InverseSurjection, fieldCount, newFieldCount);
    for (int i = 0; i < newSystemFieldCount; ++i) {
      mapping.set(i, i);
    }
    offset = systemFieldCount;
    int newOffset = newSystemFieldCount;
    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() + inputExtraFieldCounts.get(i);
    }

    if (changeCount == 0 && mapping.isIdentity()) {
      return new TrimResult(join, Mappings.createIdentity(fieldCount));
    }

    // Build new join.
    final RexVisitor<RexNode> shuttle =
        new RexPermuteInputsShuttle(mapping, newInputs.get(0), newInputs.get(1));
    RexNode newConditionExpr = conditionExpr.accept(shuttle);

    final JoinRel newJoin =
        join.copy(join.getTraitSet(), newConditionExpr, newInputs.get(0), newInputs.get(1));

    return new TrimResult(newJoin, mapping);
  }
Exemple #2
0
  /** Variant of {@link #trimFields(RelNode, BitSet, Set)} for {@link AggregateRel}. */
  public TrimResult trimFields(
      AggregateRel aggregate, BitSet fieldsUsed, Set<RelDataTypeField> extraFields) {
    // Fields:
    //
    // | sys fields | group fields | agg functions |
    //
    // Two kinds of trimming:
    //
    // 1. If agg rel has system fields but none of these are used, create an
    // agg rel with no system fields.
    //
    // 2. If aggregate functions are not used, remove them.
    //
    // But grouping fields stay, even if they are not used.

    final RelDataType rowType = aggregate.getRowType();

    // Compute which input fields are used.
    BitSet inputFieldsUsed = new BitSet();
    // 1. group fields are always used
    for (int i : Util.toIter(aggregate.getGroupSet())) {
      inputFieldsUsed.set(i);
    }
    // 2. agg functions
    for (AggregateCall aggCall : aggregate.getAggCallList()) {
      for (int i : aggCall.getArgList()) {
        inputFieldsUsed.set(i);
      }
    }

    // Create input with trimmed columns.
    final RelNode input = aggregate.getInput(0);
    final Set<RelDataTypeField> inputExtraFields = Collections.emptySet();
    final TrimResult trimResult = trimChild(aggregate, input, inputFieldsUsed, inputExtraFields);
    final RelNode newInput = trimResult.left;
    final Mapping inputMapping = trimResult.right;

    // If the input is unchanged, and we need to project all columns,
    // there's nothing to do.
    if (input == newInput && fieldsUsed.equals(Util.bitSetBetween(0, rowType.getFieldCount()))) {
      return new TrimResult(aggregate, Mappings.createIdentity(rowType.getFieldCount()));
    }

    // Which agg calls are used by our consumer?
    final int groupCount = aggregate.getGroupSet().cardinality();
    int j = groupCount;
    int usedAggCallCount = 0;
    for (int i = 0; i < aggregate.getAggCallList().size(); i++) {
      if (fieldsUsed.get(j++)) {
        ++usedAggCallCount;
      }
    }

    // Offset due to the number of system fields having changed.
    Mapping mapping =
        Mappings.create(
            MappingType.InverseSurjection, rowType.getFieldCount(), groupCount + usedAggCallCount);

    final BitSet newGroupSet = Mappings.apply(inputMapping, aggregate.getGroupSet());

    // Populate mapping of where to find the fields. System and grouping
    // fields first.
    for (IntPair pair : inputMapping) {
      if (pair.source < groupCount) {
        mapping.set(pair.source, pair.target);
      }
    }

    // Now create new agg calls, and populate mapping for them.
    final List<AggregateCall> newAggCallList = new ArrayList<AggregateCall>();
    j = groupCount;
    for (AggregateCall aggCall : aggregate.getAggCallList()) {
      if (fieldsUsed.get(j)) {
        AggregateCall newAggCall =
            new AggregateCall(
                aggCall.getAggregation(),
                aggCall.isDistinct(),
                Mappings.apply2(inputMapping, aggCall.getArgList()),
                aggCall.getType(),
                aggCall.getName());
        if (newAggCall.equals(aggCall)) {
          newAggCall = aggCall; // immutable -> canonize to save space
        }
        mapping.set(j, groupCount + newAggCallList.size());
        newAggCallList.add(newAggCall);
      }
      ++j;
    }

    RelNode newAggregate =
        new AggregateRel(aggregate.getCluster(), newInput, newGroupSet, newAggCallList);

    assert newAggregate.getClass() == aggregate.getClass();

    return new TrimResult(newAggregate, mapping);
  }
Exemple #3
0
  /** Variant of {@link #trimFields(RelNode, BitSet, Set)} for {@link ProjectRel}. */
  public TrimResult trimFields(
      ProjectRel project, BitSet fieldsUsed, Set<RelDataTypeField> extraFields) {
    final RelDataType rowType = project.getRowType();
    final int fieldCount = rowType.getFieldCount();
    final RelNode input = project.getChild();
    final RelDataType inputRowType = input.getRowType();

    // Which fields are required from the input?
    BitSet inputFieldsUsed = new BitSet(inputRowType.getFieldCount());
    final Set<RelDataTypeField> inputExtraFields = new LinkedHashSet<RelDataTypeField>(extraFields);
    RelOptUtil.InputFinder inputFinder =
        new RelOptUtil.InputFinder(inputFieldsUsed, inputExtraFields);
    for (Ord<RexNode> ord : Ord.zip(project.getProjects())) {
      if (fieldsUsed.get(ord.i)) {
        ord.e.accept(inputFinder);
      }
    }

    // Create input with trimmed columns.
    TrimResult trimResult = trimChild(project, 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 && fieldsUsed.cardinality() == fieldCount) {
      return new TrimResult(project, Mappings.createIdentity(fieldCount));
    }

    // Some parts of the system can't handle rows with zero fields, so
    // pretend that one field is used.
    if (fieldsUsed.cardinality() == 0) {
      final Mapping mapping = Mappings.create(MappingType.InverseSurjection, fieldCount, 1);
      final RexLiteral expr =
          project.getCluster().getRexBuilder().makeExactLiteral(BigDecimal.ZERO);
      RelDataType newRowType =
          project
              .getCluster()
              .getTypeFactory()
              .createStructType(
                  Collections.singletonList(expr.getType()), Collections.singletonList("DUMMY"));
      ProjectRel newProject =
          new ProjectRel(
              project.getCluster(),
              project.getCluster().traitSetOf(RelCollationImpl.EMPTY),
              newInput,
              Collections.<RexNode>singletonList(expr),
              newRowType,
              project.getFlags());
      return new TrimResult(newProject, mapping);
    }

    // Build new project expressions, and populate the mapping.
    List<RexNode> newProjectExprList = new ArrayList<RexNode>();
    final RexVisitor<RexNode> shuttle = new RexPermuteInputsShuttle(inputMapping, newInput);
    final Mapping mapping =
        Mappings.create(MappingType.InverseSurjection, fieldCount, fieldsUsed.cardinality());
    for (Ord<RexNode> ord : Ord.zip(project.getProjects())) {
      if (fieldsUsed.get(ord.i)) {
        mapping.set(ord.i, newProjectExprList.size());
        RexNode newProjectExpr = ord.e.accept(shuttle);
        newProjectExprList.add(newProjectExpr);
      }
    }

    final RelDataType newRowType =
        project
            .getCluster()
            .getTypeFactory()
            .createStructType(Mappings.apply3(mapping, rowType.getFieldList()));

    final List<RelCollation> newCollations =
        RexUtil.apply(inputMapping, project.getCollationList());

    final RelNode newProject;
    if (RemoveTrivialProjectRule.isIdentity(
        newProjectExprList, newRowType, newInput.getRowType())) {
      // The new project would be the identity. It is equivalent to return
      // its child.
      newProject = newInput;
    } else {
      newProject =
          new ProjectRel(
              project.getCluster(),
              project
                  .getCluster()
                  .traitSetOf(
                      newCollations.isEmpty() ? RelCollationImpl.EMPTY : newCollations.get(0)),
              newInput,
              newProjectExprList,
              newRowType,
              project.getFlags());
      assert newProject.getClass() == project.getClass();
    }
    return new TrimResult(newProject, mapping);
  }