Function getTableFormattedOutput

src/Interpreters/InterpreterShowStatsQuery.cpp:60–127

std::vector<FormattedOutputData> getTableFormattedOutput(
    ContextPtr context,
    CatalogAdaptorPtr catalog,
    const CollectorSettings & collector_settings,
    const StatsTableIdentifier & table_info,
    const std::vector<String> & column_names)
{
    std::vector<FormattedOutputData> results;
    StatisticsCollector collector_impl(context, catalog, table_info, collector_settings);
    if (column_names.empty())
    {
        collector_impl.readAllFromCatalog();
    }
    else
    {
        auto cols_desc = catalog->filterCollectableColumns(table_info, column_names, true);
        collector_impl.readFromCatalogImpl(cols_desc);
    }


    auto plannode_stats_opt = collector_impl.toPlanNodeStatistics();
    if (!plannode_stats_opt.has_value())
    {
        return {};
    }

    auto plannode_stats = plannode_stats_opt.value();

    auto row_count = plannode_stats->getRowCount();
    {
        FormattedOutputData fod;
        fod.append("identifier", table_info.getTableName() + ".*");
        fod.append("count", row_count);
        results.emplace_back(std::move(fod));
    }

    auto symbols = plannode_stats->getSymbolStatistics();
    auto cols_desc = catalog->getAllCollectableColumns(table_info);
    for (auto & col : cols_desc)
    {
        auto symbol_iter = symbols.find(col.name);
        if (symbol_iter == symbols.end())
        {
            // TODO: should we output empty columns? to ensure no stats is correctly handled
            continue;
        }
        auto & symbol_stats = symbol_iter->second;

        FormattedOutputData fod;

        auto type_name = col.type->getName();
        fod.append("identifier", table_info.getTableName() + "." + col.name);
        fod.append("type", type_name);
        auto ndv = symbol_stats->getNdv();
        fod.append("ndv", ndv);

        auto null_count = symbol_stats->getNullsCount();
        fod.append("count", row_count - null_count);