private void evaluateMergeWork(MergeJoinWork w) throws SemanticException {
      for (BaseWork baseWork : w.getBaseWorkList()) {
        evaluateOperators(baseWork, pctx);
      }
    }
SerializeFilter is a simple physical optimizer that serializes all filter expressions in
Tablescan Operators.
ql/src/java/org/apache/hadoop/hive/ql/optimizer/physical/SerializeFilter.java