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

Example 1 with MetadataControllerPrel

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

the class StarColumnConverter method visitPrel.

@Override
public Prel visitPrel(Prel prel, Void value) throws RuntimeException {
    if (prel instanceof MetadataControllerPrel) {
        // disallow renaming projections for analyze command
        return prel;
    }
    // Require prefix rename : there exists other expression, in addition to a star column.
    if (// not set yet.
    !prefixedForStar && StarColumnHelper.containsStarColumn(prel.getRowType()) && prel.getRowType().getFieldNames().size() > 1) {
        prefixedForStar = true;
    }
    List<RelNode> children = Lists.newArrayList();
    for (Prel child : prel) {
        child = child.accept(this, null);
        children.add(child);
    }
    return (Prel) prel.copy(prel.getTraitSet(), children);
}