Examples with DrillFuncHolderExpr org.apache.drill.exec.expr.DrillFuncHolderExpr used on opensource projects

Example 1 with DrillFuncHolderExpr

use of org.apache.drill.exec.expr.DrillFuncHolderExpr in project drill by apache.

the class FlattenRecordBatch method setupNewSchema.

@Override
protected boolean setupNewSchema() {
    allocationVectors = new ArrayList<>();
    container.clear();
    List<NamedExpression> exprs = getExpressionList();
    ErrorCollector collector = new ErrorCollectorImpl();
    List<TransferPair> transfers = new ArrayList<>();
    ClassGenerator<Flattener> cg = CodeGenerator.getRoot(Flattener.TEMPLATE_DEFINITION, context.getOptions());
    cg.getCodeGenerator().plainJavaCapable(true);
    IntHashSet transferFieldIds = new IntHashSet();
    NamedExpression flattenExpr = new NamedExpression(popConfig.getColumn(), new FieldReference(popConfig.getColumn()));
    ValueVectorReadExpression vectorRead = (ValueVectorReadExpression) ExpressionTreeMaterializer.materialize(flattenExpr.getExpr(), incoming, collector, context.getFunctionRegistry(), true);
    FieldReference fieldReference = flattenExpr.getRef();
    TransferPair transferPair = getFlattenFieldTransferPair(fieldReference);
    if (transferPair != null) {
        ValueVector flattenVector = transferPair.getTo();
        // checks that list has only default ValueVector and replaces resulting ValueVector to INT typed ValueVector
        if (exprs.size() == 0 && flattenVector.getField().getType().equals(Types.LATE_BIND_TYPE)) {
            MaterializedField outputField = MaterializedField.create(fieldReference.getAsNamePart().getName(), Types.OPTIONAL_INT);
            ValueVector vector = TypeHelper.getNewVector(outputField, oContext.getAllocator());
            container.add(vector);
        } else {
            transfers.add(transferPair);
            container.add(flattenVector);
            transferFieldIds.add(vectorRead.getFieldId().getFieldIds()[0]);
        }
    }
    logger.debug("Added transfer for project expression.");
    ClassifierResult result = new ClassifierResult();
    for (NamedExpression namedExpression : exprs) {
        result.clear();
        String outputName = getRef(namedExpression).getRootSegment().getPath();
        if (result != null && result.outputNames != null && result.outputNames.size() > 0) {
            for (int j = 0; j < result.outputNames.size(); j++) {
                if (!result.outputNames.get(j).equals(EMPTY_STRING)) {
                    outputName = result.outputNames.get(j);
                    break;
                }
            }
        }
        LogicalExpression expr = ExpressionTreeMaterializer.materialize(namedExpression.getExpr(), incoming, collector, context.getFunctionRegistry(), true);
        collector.reportErrors(logger);
        if (expr instanceof DrillFuncHolderExpr && ((DrillFuncHolderExpr) expr).getHolder().isComplexWriterFuncHolder()) {
            // Lazy initialization of the list of complex writers, if not done yet.
            if (complexWriters == null) {
                complexWriters = new ArrayList<>();
            }
            // The reference name will be passed to ComplexWriter, used as the name of the output vector from the writer.
            ((DrillFuncHolderExpr) expr).setFieldReference(namedExpression.getRef());
            cg.addExpr(expr);
        } else {
            // need to do evaluation.
            MaterializedField outputField;
            if (expr instanceof ValueVectorReadExpression) {
                TypedFieldId id = ValueVectorReadExpression.class.cast(expr).getFieldId();
                ValueVector incomingVector = incoming.getValueAccessorById(id.getIntermediateClass(), id.getFieldIds()).getValueVector();
                // when the first batch will be empty.
                if (incomingVector != null) {
                    outputField = incomingVector.getField().clone();
                } else {
                    outputField = MaterializedField.create(outputName, expr.getMajorType());
                }
            } else {
                outputField = MaterializedField.create(outputName, expr.getMajorType());
            }
            ValueVector vector = TypeHelper.getNewVector(outputField, oContext.getAllocator());
            allocationVectors.add(vector);
            TypedFieldId fid = container.add(vector);
            ValueVectorWriteExpression write = new ValueVectorWriteExpression(fid, expr, true);
            cg.addExpr(write);
            logger.debug("Added eval for project expression.");
        }
    }
    cg.rotateBlock();
    cg.getEvalBlock()._return(JExpr.TRUE);
    container.buildSchema(SelectionVectorMode.NONE);
    try {
        flattener = context.getImplementationClass(cg.getCodeGenerator());
        flattener.setup(context, incoming, this, transfers);
    } catch (SchemaChangeException e) {
        throw schemaChangeException(e, logger);
    }
    return true;
}

Example 2 with DrillFuncHolderExpr

use of org.apache.drill.exec.expr.DrillFuncHolderExpr in project drill by apache.

the class StreamingAggBatch method createAggregatorInternal.

protected StreamingAggregator createAggregatorInternal() {
    ClassGenerator<StreamingAggregator> cg = CodeGenerator.getRoot(StreamingAggTemplate.TEMPLATE_DEFINITION, context.getOptions());
    // Streaming agg no longer plain Java capable. Stats generates code
    // that fails when compiled normally.
    // cannot override resetValues() in org.apache.drill.exec.physical.impl.aggregate.StreamingAggTemplate
    // public boolean resetValues()
    // ^
    // overridden method does not throw org.apache.drill.exec.exception.SchemaChangeException (compiler.err.override.meth.doesnt.throw)
    // cg.getCodeGenerator().plainJavaCapable(true);
    // Uncomment out this line to debug the generated code.
    // cg.getCodeGenerator().saveCodeForDebugging(true);
    container.clear();
    LogicalExpression[] keyExprs = new LogicalExpression[getKeyExpressions().size()];
    LogicalExpression[] valueExprs = new LogicalExpression[getValueExpressions().size()];
    TypedFieldId[] keyOutputIds = new TypedFieldId[getKeyExpressions().size()];
    ErrorCollector collector = new ErrorCollectorImpl();
    for (int i = 0; i < keyExprs.length; i++) {
        NamedExpression ne = getKeyExpressions().get(i);
        LogicalExpression expr = ExpressionTreeMaterializer.materialize(ne.getExpr(), incoming, collector, context.getFunctionRegistry());
        if (expr == null) {
            continue;
        }
        keyExprs[i] = expr;
        MaterializedField outputField = MaterializedField.create(ne.getRef().getLastSegment().getNameSegment().getPath(), expr.getMajorType());
        container.addOrGet(outputField);
        keyOutputIds[i] = container.getValueVectorId(ne.getRef());
    }
    for (int i = 0; i < valueExprs.length; i++) {
        NamedExpression ne = getValueExpressions().get(i);
        LogicalExpression expr = ExpressionTreeMaterializer.materialize(ne.getExpr(), incoming, collector, context.getFunctionRegistry(), true, false);
        if (expr instanceof IfExpression) {
            throw UserException.unsupportedError(new UnsupportedOperationException("Union type not supported in aggregate functions")).build(logger);
        }
        if (expr == null) {
            continue;
        }
        // Populate the complex writers for complex exprs
        if (expr instanceof DrillFuncHolderExpr && ((DrillFuncHolderExpr) expr).getHolder().isComplexWriterFuncHolder()) {
            // Lazy initialization of the list of complex writers, if not done yet.
            if (complexWriters == null) {
                complexWriters = Lists.newArrayList();
            } else {
                complexWriters.clear();
            }
            // The reference name will be passed to ComplexWriter, used as the name of the output vector from the writer.
            ((DrillFuncHolderExpr) expr).setFieldReference(ne.getRef());
            MaterializedField field = MaterializedField.create(ne.getRef().getAsNamePart().getName(), UntypedNullHolder.TYPE);
            container.add(new UntypedNullVector(field, container.getAllocator()));
            valueExprs[i] = expr;
        } else {
            MaterializedField outputField = MaterializedField.create(ne.getRef().getLastSegment().getNameSegment().getPath(), expr.getMajorType());
            container.addOrGet(outputField);
            TypedFieldId id = container.getValueVectorId(ne.getRef());
            valueExprs[i] = new ValueVectorWriteExpression(id, expr, true);
        }
    }
    collector.reportErrors(logger);
    setupIsSame(cg, keyExprs);
    setupIsSameApart(cg, keyExprs);
    addRecordValues(cg, valueExprs);
    outputRecordKeys(cg, keyOutputIds, keyExprs);
    outputRecordKeysPrev(cg, keyOutputIds, keyExprs);
    cg.getBlock("resetValues")._return(JExpr.TRUE);
    getIndex(cg);
    container.buildSchema(SelectionVectorMode.NONE);
    StreamingAggregator agg = context.getImplementationClass(cg);
    try {
        agg.setup(oContext, incoming, this, maxOutputRowCount);
    } catch (SchemaChangeException e) {
        throw schemaChangeException(e, logger);
    }
    allocateComplexWriters();
    return agg;
}

Example 3 with DrillFuncHolderExpr

use of org.apache.drill.exec.expr.DrillFuncHolderExpr in project drill by apache.

the class ProjectionMaterializer method setupExpression.

private void setupExpression(NamedExpression namedExpression) {
    result.clear();
    if (classify && namedExpression.getExpr() instanceof SchemaPath) {
        classifyExpr(namedExpression, result);
        if (result.isStar) {
            setupImplicitColumnRef(namedExpression);
            return;
        }
    } else {
        // For the columns which do not needed to be classified,
        // it is still necessary to ensure the output column name is unique
        result.outputNames = new ArrayList<>();
        // moved
        String outputName = getRef(namedExpression).getRootSegment().getPath();
        // to
        // before
        // the
        // if
        addToResultMaps(outputName, result, true);
    }
    String outputName = getRef(namedExpression).getRootSegment().getPath();
    if (result != null && result.outputNames != null && result.outputNames.size() > 0) {
        boolean isMatched = false;
        for (int j = 0; j < result.outputNames.size(); j++) {
            if (!result.outputNames.get(j).isEmpty()) {
                outputName = result.outputNames.get(j);
                isMatched = true;
                break;
            }
        }
        if (!isMatched) {
            return;
        }
    }
    LogicalExpression expr = ExpressionTreeMaterializer.materialize(namedExpression.getExpr(), incomingBatch, collector, functionLookupContext, true, unionTypeEnabled);
    collector.reportErrors(logger);
    // otherwise, add to evaluation stack.
    if (expr instanceof ValueVectorReadExpression && incomingSchema.getSelectionVectorMode() == SelectionVectorMode.NONE && !((ValueVectorReadExpression) expr).hasReadPath() && !isAnyWildcard && !transferFieldIds.contains(((ValueVectorReadExpression) expr).getFieldId().getFieldIds()[0])) {
        setupDirectTransfer(namedExpression, expr);
    } else if (expr instanceof DrillFuncHolderExpr && ((DrillFuncHolderExpr) expr).getHolder().isComplexWriterFuncHolder()) {
        setupFnCall(namedExpression, expr);
    } else {
        // need to do evaluation.
        setupExprEval(namedExpression, expr, outputName);
    }
}

Example 4 with DrillFuncHolderExpr

use of org.apache.drill.exec.expr.DrillFuncHolderExpr in project drill by apache.

the class ProjectRecordBatch method setupNewSchema.

@Override
protected boolean setupNewSchema() throws SchemaChangeException {
    if (allocationVectors != null) {
        for (final ValueVector v : allocationVectors) {
            v.clear();
        }
    }
    this.allocationVectors = Lists.newArrayList();
    if (complexWriters != null) {
        container.clear();
    } else {
        container.zeroVectors();
    }
    final List<NamedExpression> exprs = getExpressionList();
    final ErrorCollector collector = new ErrorCollectorImpl();
    final List<TransferPair> transfers = Lists.newArrayList();
    final ClassGenerator<Projector> cg = CodeGenerator.getRoot(Projector.TEMPLATE_DEFINITION, context.getFunctionRegistry(), context.getOptions());
    cg.getCodeGenerator().plainJavaCapable(true);
    // Uncomment out this line to debug the generated code.
    //    cg.getCodeGenerator().saveCodeForDebugging(true);
    final IntHashSet transferFieldIds = new IntHashSet();
    final boolean isAnyWildcard = isAnyWildcard(exprs);
    final ClassifierResult result = new ClassifierResult();
    final boolean classify = isClassificationNeeded(exprs);
    for (int i = 0; i < exprs.size(); i++) {
        final NamedExpression namedExpression = exprs.get(i);
        result.clear();
        if (classify && namedExpression.getExpr() instanceof SchemaPath) {
            classifyExpr(namedExpression, incoming, result);
            if (result.isStar) {
                // The value indicates which wildcard we are processing now
                final Integer value = result.prefixMap.get(result.prefix);
                if (value != null && value.intValue() == 1) {
                    int k = 0;
                    for (final VectorWrapper<?> wrapper : incoming) {
                        final ValueVector vvIn = wrapper.getValueVector();
                        if (k > result.outputNames.size() - 1) {
                            assert false;
                        }
                        // get the renamed column names
                        final String name = result.outputNames.get(k++);
                        if (name == EMPTY_STRING) {
                            continue;
                        }
                        if (isImplicitFileColumn(vvIn)) {
                            continue;
                        }
                        final FieldReference ref = new FieldReference(name);
                        final ValueVector vvOut = container.addOrGet(MaterializedField.create(ref.getAsNamePart().getName(), vvIn.getField().getType()), callBack);
                        final TransferPair tp = vvIn.makeTransferPair(vvOut);
                        transfers.add(tp);
                    }
                } else if (value != null && value.intValue() > 1) {
                    // subsequent wildcards should do a copy of incoming valuevectors
                    int k = 0;
                    for (final VectorWrapper<?> wrapper : incoming) {
                        final ValueVector vvIn = wrapper.getValueVector();
                        final SchemaPath originalPath = SchemaPath.getSimplePath(vvIn.getField().getPath());
                        if (k > result.outputNames.size() - 1) {
                            assert false;
                        }
                        // get the renamed column names
                        final String name = result.outputNames.get(k++);
                        if (name == EMPTY_STRING) {
                            continue;
                        }
                        if (isImplicitFileColumn(vvIn)) {
                            continue;
                        }
                        final LogicalExpression expr = ExpressionTreeMaterializer.materialize(originalPath, incoming, collector, context.getFunctionRegistry());
                        if (collector.hasErrors()) {
                            throw new SchemaChangeException(String.format("Failure while trying to materialize incoming schema.  Errors:\n %s.", collector.toErrorString()));
                        }
                        final MaterializedField outputField = MaterializedField.create(name, expr.getMajorType());
                        final ValueVector vv = container.addOrGet(outputField, callBack);
                        allocationVectors.add(vv);
                        final TypedFieldId fid = container.getValueVectorId(SchemaPath.getSimplePath(outputField.getPath()));
                        final ValueVectorWriteExpression write = new ValueVectorWriteExpression(fid, expr, true);
                        final HoldingContainer hc = cg.addExpr(write, ClassGenerator.BlkCreateMode.TRUE_IF_BOUND);
                    }
                }
                continue;
            }
        } else {
            // For the columns which do not needed to be classified,
            // it is still necessary to ensure the output column name is unique
            result.outputNames = Lists.newArrayList();
            final String outputName = getRef(namedExpression).getRootSegment().getPath();
            addToResultMaps(outputName, result, true);
        }
        String outputName = getRef(namedExpression).getRootSegment().getPath();
        if (result != null && result.outputNames != null && result.outputNames.size() > 0) {
            boolean isMatched = false;
            for (int j = 0; j < result.outputNames.size(); j++) {
                if (!result.outputNames.get(j).equals(EMPTY_STRING)) {
                    outputName = result.outputNames.get(j);
                    isMatched = true;
                    break;
                }
            }
            if (!isMatched) {
                continue;
            }
        }
        final LogicalExpression expr = ExpressionTreeMaterializer.materialize(namedExpression.getExpr(), incoming, collector, context.getFunctionRegistry(), true, unionTypeEnabled);
        final MaterializedField outputField = MaterializedField.create(outputName, expr.getMajorType());
        if (collector.hasErrors()) {
            throw new SchemaChangeException(String.format("Failure while trying to materialize incoming schema.  Errors:\n %s.", collector.toErrorString()));
        }
        // add value vector to transfer if direct reference and this is allowed, otherwise, add to evaluation stack.
        if (expr instanceof ValueVectorReadExpression && incoming.getSchema().getSelectionVectorMode() == SelectionVectorMode.NONE && !((ValueVectorReadExpression) expr).hasReadPath() && !isAnyWildcard && !transferFieldIds.contains(((ValueVectorReadExpression) expr).getFieldId().getFieldIds()[0])) {
            final ValueVectorReadExpression vectorRead = (ValueVectorReadExpression) expr;
            final TypedFieldId id = vectorRead.getFieldId();
            final ValueVector vvIn = incoming.getValueAccessorById(id.getIntermediateClass(), id.getFieldIds()).getValueVector();
            Preconditions.checkNotNull(incoming);
            final FieldReference ref = getRef(namedExpression);
            final ValueVector vvOut = container.addOrGet(MaterializedField.create(ref.getAsUnescapedPath(), vectorRead.getMajorType()), callBack);
            final TransferPair tp = vvIn.makeTransferPair(vvOut);
            transfers.add(tp);
            transferFieldIds.add(vectorRead.getFieldId().getFieldIds()[0]);
        } else if (expr instanceof DrillFuncHolderExpr && ((DrillFuncHolderExpr) expr).getHolder().isComplexWriterFuncHolder()) {
            // Lazy initialization of the list of complex writers, if not done yet.
            if (complexWriters == null) {
                complexWriters = Lists.newArrayList();
            } else {
                complexWriters.clear();
            }
            // The reference name will be passed to ComplexWriter, used as the name of the output vector from the writer.
            ((DrillFuncHolderExpr) expr).getFieldReference(namedExpression.getRef());
            cg.addExpr(expr, ClassGenerator.BlkCreateMode.TRUE_IF_BOUND);
            if (complexFieldReferencesList == null) {
                complexFieldReferencesList = Lists.newArrayList();
            }
            // save the field reference for later for getting schema when input is empty
            complexFieldReferencesList.add(namedExpression.getRef());
        } else {
            // need to do evaluation.
            final ValueVector vector = container.addOrGet(outputField, callBack);
            allocationVectors.add(vector);
            final TypedFieldId fid = container.getValueVectorId(SchemaPath.getSimplePath(outputField.getPath()));
            final boolean useSetSafe = !(vector instanceof FixedWidthVector);
            final ValueVectorWriteExpression write = new ValueVectorWriteExpression(fid, expr, useSetSafe);
            final HoldingContainer hc = cg.addExpr(write, ClassGenerator.BlkCreateMode.TRUE_IF_BOUND);
            // We cannot do multiple transfers from the same vector. However we still need to instantiate the output vector.
            if (expr instanceof ValueVectorReadExpression) {
                final ValueVectorReadExpression vectorRead = (ValueVectorReadExpression) expr;
                if (!vectorRead.hasReadPath()) {
                    final TypedFieldId id = vectorRead.getFieldId();
                    final ValueVector vvIn = incoming.getValueAccessorById(id.getIntermediateClass(), id.getFieldIds()).getValueVector();
                    vvIn.makeTransferPair(vector);
                }
            }
            logger.debug("Added eval for project expression.");
        }
    }
    try {
        CodeGenerator<Projector> codeGen = cg.getCodeGenerator();
        codeGen.plainJavaCapable(true);
        // Uncomment out this line to debug the generated code.
        //      codeGen.saveCodeForDebugging(true);
        this.projector = context.getImplementationClass(codeGen);
        projector.setup(context, incoming, this, transfers);
    } catch (ClassTransformationException | IOException e) {
        throw new SchemaChangeException("Failure while attempting to load generated class", e);
    }
    if (container.isSchemaChanged()) {
        container.buildSchema(SelectionVectorMode.NONE);
        return true;
    } else {
        return false;
    }
}

Example 5 with DrillFuncHolderExpr

use of org.apache.drill.exec.expr.DrillFuncHolderExpr in project drill by axbaretto.

the class ProjectRecordBatch method setupNewSchemaFromInput.

private void setupNewSchemaFromInput(RecordBatch incomingBatch) throws SchemaChangeException {
    if (allocationVectors != null) {
        for (final ValueVector v : allocationVectors) {
            v.clear();
        }
    }
    this.allocationVectors = Lists.newArrayList();
    if (complexWriters != null) {
        container.clear();
    } else {
        container.zeroVectors();
    }
    final List<NamedExpression> exprs = getExpressionList();
    final ErrorCollector collector = new ErrorCollectorImpl();
    final List<TransferPair> transfers = Lists.newArrayList();
    final ClassGenerator<Projector> cg = CodeGenerator.getRoot(Projector.TEMPLATE_DEFINITION, context.getOptions());
    cg.getCodeGenerator().plainJavaCapable(true);
    // Uncomment out this line to debug the generated code.
    // cg.getCodeGenerator().saveCodeForDebugging(true);
    final IntHashSet transferFieldIds = new IntHashSet();
    final boolean isAnyWildcard = isAnyWildcard(exprs);
    final ClassifierResult result = new ClassifierResult();
    final boolean classify = isClassificationNeeded(exprs);
    for (NamedExpression namedExpression : exprs) {
        result.clear();
        if (classify && namedExpression.getExpr() instanceof SchemaPath) {
            classifyExpr(namedExpression, incomingBatch, result);
            if (result.isStar) {
                // The value indicates which wildcard we are processing now
                final Integer value = result.prefixMap.get(result.prefix);
                if (value != null && value == 1) {
                    int k = 0;
                    for (final VectorWrapper<?> wrapper : incomingBatch) {
                        final ValueVector vvIn = wrapper.getValueVector();
                        if (k > result.outputNames.size() - 1) {
                            assert false;
                        }
                        // get the renamed column names
                        final String name = result.outputNames.get(k++);
                        if (name.isEmpty()) {
                            continue;
                        }
                        if (isImplicitFileColumn(vvIn)) {
                            continue;
                        }
                        final FieldReference ref = new FieldReference(name);
                        final ValueVector vvOut = container.addOrGet(MaterializedField.create(ref.getAsNamePart().getName(), vvIn.getField().getType()), callBack);
                        final TransferPair tp = vvIn.makeTransferPair(vvOut);
                        transfers.add(tp);
                    }
                } else if (value != null && value > 1) {
                    // subsequent wildcards should do a copy of incoming valuevectors
                    int k = 0;
                    for (final VectorWrapper<?> wrapper : incomingBatch) {
                        final ValueVector vvIn = wrapper.getValueVector();
                        final SchemaPath originalPath = SchemaPath.getSimplePath(vvIn.getField().getName());
                        if (k > result.outputNames.size() - 1) {
                            assert false;
                        }
                        // get the renamed column names
                        final String name = result.outputNames.get(k++);
                        if (name.isEmpty()) {
                            continue;
                        }
                        if (isImplicitFileColumn(vvIn)) {
                            continue;
                        }
                        final LogicalExpression expr = ExpressionTreeMaterializer.materialize(originalPath, incomingBatch, collector, context.getFunctionRegistry());
                        if (collector.hasErrors()) {
                            throw new SchemaChangeException(String.format("Failure while trying to materialize incomingBatch schema.  Errors:\n %s.", collector.toErrorString()));
                        }
                        final MaterializedField outputField = MaterializedField.create(name, expr.getMajorType());
                        final ValueVector vv = container.addOrGet(outputField, callBack);
                        allocationVectors.add(vv);
                        final TypedFieldId fid = container.getValueVectorId(SchemaPath.getSimplePath(outputField.getName()));
                        final ValueVectorWriteExpression write = new ValueVectorWriteExpression(fid, expr, true);
                        final HoldingContainer hc = cg.addExpr(write, ClassGenerator.BlkCreateMode.TRUE_IF_BOUND);
                    }
                }
                continue;
            }
        } else {
            // For the columns which do not needed to be classified,
            // it is still necessary to ensure the output column name is unique
            result.outputNames = Lists.newArrayList();
            final String outputName = getRef(namedExpression).getRootSegment().getPath();
            addToResultMaps(outputName, result, true);
        }
        String outputName = getRef(namedExpression).getRootSegment().getPath();
        if (result != null && result.outputNames != null && result.outputNames.size() > 0) {
            boolean isMatched = false;
            for (int j = 0; j < result.outputNames.size(); j++) {
                if (!result.outputNames.get(j).isEmpty()) {
                    outputName = result.outputNames.get(j);
                    isMatched = true;
                    break;
                }
            }
            if (!isMatched) {
                continue;
            }
        }
        final LogicalExpression expr = ExpressionTreeMaterializer.materialize(namedExpression.getExpr(), incomingBatch, collector, context.getFunctionRegistry(), true, unionTypeEnabled);
        final MaterializedField outputField = MaterializedField.create(outputName, expr.getMajorType());
        if (collector.hasErrors()) {
            throw new SchemaChangeException(String.format("Failure while trying to materialize incoming schema.  Errors:\n %s.", collector.toErrorString()));
        }
        // add value vector to transfer if direct reference and this is allowed, otherwise, add to evaluation stack.
        if (expr instanceof ValueVectorReadExpression && incomingBatch.getSchema().getSelectionVectorMode() == SelectionVectorMode.NONE && !((ValueVectorReadExpression) expr).hasReadPath() && !isAnyWildcard && !transferFieldIds.contains(((ValueVectorReadExpression) expr).getFieldId().getFieldIds()[0])) {
            final ValueVectorReadExpression vectorRead = (ValueVectorReadExpression) expr;
            final TypedFieldId id = vectorRead.getFieldId();
            final ValueVector vvIn = incomingBatch.getValueAccessorById(id.getIntermediateClass(), id.getFieldIds()).getValueVector();
            Preconditions.checkNotNull(incomingBatch);
            final FieldReference ref = getRef(namedExpression);
            final ValueVector vvOut = container.addOrGet(MaterializedField.create(ref.getLastSegment().getNameSegment().getPath(), vectorRead.getMajorType()), callBack);
            final TransferPair tp = vvIn.makeTransferPair(vvOut);
            transfers.add(tp);
            transferFieldIds.add(vectorRead.getFieldId().getFieldIds()[0]);
        } else if (expr instanceof DrillFuncHolderExpr && ((DrillFuncHolderExpr) expr).getHolder().isComplexWriterFuncHolder()) {
            // Lazy initialization of the list of complex writers, if not done yet.
            if (complexWriters == null) {
                complexWriters = Lists.newArrayList();
            } else {
                complexWriters.clear();
            }
            // The reference name will be passed to ComplexWriter, used as the name of the output vector from the writer.
            ((DrillFuncHolderExpr) expr).getFieldReference(namedExpression.getRef());
            cg.addExpr(expr, ClassGenerator.BlkCreateMode.TRUE_IF_BOUND);
            if (complexFieldReferencesList == null) {
                complexFieldReferencesList = Lists.newArrayList();
            }
            // save the field reference for later for getting schema when input is empty
            complexFieldReferencesList.add(namedExpression.getRef());
        } else {
            // need to do evaluation.
            final ValueVector vector = container.addOrGet(outputField, callBack);
            allocationVectors.add(vector);
            final TypedFieldId fid = container.getValueVectorId(SchemaPath.getSimplePath(outputField.getName()));
            final boolean useSetSafe = !(vector instanceof FixedWidthVector);
            final ValueVectorWriteExpression write = new ValueVectorWriteExpression(fid, expr, useSetSafe);
            final HoldingContainer hc = cg.addExpr(write, ClassGenerator.BlkCreateMode.TRUE_IF_BOUND);
            // We cannot do multiple transfers from the same vector. However we still need to instantiate the output vector.
            if (expr instanceof ValueVectorReadExpression) {
                final ValueVectorReadExpression vectorRead = (ValueVectorReadExpression) expr;
                if (!vectorRead.hasReadPath()) {
                    final TypedFieldId id = vectorRead.getFieldId();
                    final ValueVector vvIn = incomingBatch.getValueAccessorById(id.getIntermediateClass(), id.getFieldIds()).getValueVector();
                    vvIn.makeTransferPair(vector);
                }
            }
            logger.debug("Added eval for project expression.");
        }
    }
    try {
        CodeGenerator<Projector> codeGen = cg.getCodeGenerator();
        codeGen.plainJavaCapable(true);
        // Uncomment out this line to debug the generated code.
        // codeGen.saveCodeForDebugging(true);
        this.projector = context.getImplementationClass(codeGen);
        projector.setup(context, incomingBatch, this, transfers);
    } catch (ClassTransformationException | IOException e) {
        throw new SchemaChangeException("Failure while attempting to load generated class", e);
    }
}