static boolean isUnknownState(ExprNodeDesc descNd) {
    boolean unknown = false;
    if ((descNd == null)
        || (descNd instanceof ExprNodeConstantDesc
        && ((ExprNodeConstantDesc) descNd).getValue() == null)) {
      unknown = true;
    }
    return unknown;
  }
Check if the node is unknown


unknown is marked in {@link #transform(ParseContext)} <blockquote>

<pre>
newcd = new ExprNodeConstantDesc(cd.getTypeInfo(), null)
</pre>

like

1. non-skewed column

2. non and/or/not ...


@param descNd
@return
ql/src/java/org/apache/hadoop/hive/ql/optimizer/listbucketingpruner/ListBucketingPrunerUtils.java