Method ExprSet

bolt/expression/Expr.cpp:1847–1858

    const exec::Expr& expr,
    std::unordered_map<std::string, exec::ExprStats>& stats,
    std::unordered_set<const exec::Expr*>& uniqueExprs) {
  auto it = uniqueExprs.find(&expr);
  if (it != uniqueExprs.end()) {
    // Common sub-expression. Skip to avoid double counting.
    return;
  }

  uniqueExprs.insert(&expr);

  // Do not aggregate empty stats.
  if (expr.stats().numProcessedRows) {
    stats[expr.name()].add(expr.stats());
  }

  for (const auto& input : expr.inputs()) {