Examples with FlattenPrel org.apache.drill.exec.planner.physical.FlattenPrel used on opensource projects

Example 1 with FlattenPrel

use of org.apache.drill.exec.planner.physical.FlattenPrel in project drill by apache.

the class RewriteProjectToFlatten method visitProject.

@Override
public Prel visitProject(ProjectPrel node, Object unused) throws RelConversionException {
    ProjectPrel project = node;
    List<RexNode> exprList = new ArrayList<>();
    boolean rewrite = false;
    List<RelDataTypeField> relDataTypes = new ArrayList<>();
    int i = 0;
    RexNode flatttenExpr = null;
    for (RexNode rex : project.getChildExps()) {
        RexNode newExpr = rex;
        if (rex instanceof RexCall) {
            RexCall function = (RexCall) rex;
            String functionName = function.getOperator().getName();
            if (functionName.equalsIgnoreCase("flatten")) {
                rewrite = true;
                if (function.getOperands().size() != 1) {
                    throw new RelConversionException("Flatten expression expects a single input.");
                }
                newExpr = function.getOperands().get(0);
                RexBuilder builder = new RexBuilder(factory);
                flatttenExpr = builder.makeInputRef(new RelDataTypeDrillImpl(new RelDataTypeHolder(), factory), i);
            }
        }
        relDataTypes.add(project.getRowType().getFieldList().get(i));
        i++;
        exprList.add(newExpr);
    }
    if (rewrite == true) {
        // TODO - figure out what is the right setting for the traits
        Prel newChild = ((Prel) project.getInput(0)).accept(this, null);
        ProjectPrel newProject = new ProjectPrel(node.getCluster(), project.getTraitSet(), newChild, exprList, new RelRecordType(relDataTypes));
        FlattenPrel flatten = new FlattenPrel(project.getCluster(), project.getTraitSet(), newProject, flatttenExpr);
        return flatten;
    }
    Prel child = ((Prel) project.getInput()).accept(this, null);
    return (Prel) project.copy(project.getTraitSet(), child, exprList, new RelRecordType(relDataTypes));
}