presto-main/src/main/java/io/prestosql/cost/ValuesStatsRule.java/ValuesStatsRule/calculate
class ValuesStatsRule:    @Override
    public Optional<PlanNodeStatsEstimate> calculate(ValuesNode node, StatsProvider sourceStats, Lookup lookup, Session session, TypeProvider types)
    {
        PlanNodeStatsEstimate.Builder statsBuilder = PlanNodeStatsEstimate.builder();
        statsBuilder.setOutputRowCount(node.getRows().size());

        for (int symbolId = 0; symbolId < node.getOutputSymbols().size(); ++symbolId) {
            Symbol symbol = node.getOutputSymbols().get(symbolId);
            List<Object> symbolValues = getSymbolValues(node, symbolId, session, types.get(symbol));
            statsBuilder.addSymbolStatistics(symbol, buildSymbolStatistics(symbolValues, session, types.get(symbol)));
        }

        return Optional.of(statsBuilder.build());
    }