public VectorExpression[] getVectorExpressionsUpConvertDecimal64(List<ExprNodeDesc> exprNodes)
      throws HiveException {
    VectorExpression[] vecExprs =
        getVectorExpressions(exprNodes, VectorExpressionDescriptor.Mode.PROJECTION);
    final int size = vecExprs.length;
    for (int i = 0; i < size; i++) {
      VectorExpression vecExpr = vecExprs[i];
      if (vecExpr.getOutputColumnVectorType() == ColumnVector.Type.DECIMAL_64) {
        vecExprs[i] = wrapWithDecimal64ToDecimalConversion(vecExpr);
      }
    }
    return vecExprs;
  }
Frees up actually marked scract columns.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/VectorizationContext.java