private void parseStreamTables(QBJoinTree joinTree, QB qb) {
    List<String> streamAliases = joinTree.getStreamAliases();

    for (Node hintNode : qb.getParseInfo().getHints().getChildren()) {
      ASTNode hint = (ASTNode) hintNode;
      if (hint.getChild(0).getType() == HintParser.TOK_STREAMTABLE) {
        for (int i = 0; i < hint.getChild(1).getChildCount(); i++) {
          if (streamAliases == null) {
            streamAliases = new ArrayList<String>();
          }
          streamAliases.add(hint.getChild(1).getChild(i).getText());
        }
      }
    }

    joinTree.setStreamAliases(streamAliases);
  }
Extract the filters from the join condition and push them on top of the
source operators. This procedure traverses the query tree recursively,
ql/src/java/org/apache/hadoop/hive/ql/parse/SemanticAnalyzer.java