ClickHouse/src/Storages/System/StorageSystemNamedCollections.cpp

#include "StorageSystemNamedCollections.h"

#include <Common/FieldVisitorToString.h>
#include <DataTypes/DataTypeString.h>
#include <DataTypes/DataTypeMap.h>
#include <Interpreters/Context.h>
#include <Interpreters/ProfileEventsExt.h>
#include <Access/Common/AccessType.h>
#include <Access/Common/AccessFlags.h>
#include <Columns/ColumnMap.h>
#include <Storages/NamedCollections.h>


namespace DB
{

NamesAndTypesList StorageSystemNamedCollections::getNamesAndTypes()
{
    return {
        {"name", std::make_shared<DataTypeString>()},
        {"collection", std::make_shared<DataTypeMap>(std::make_shared<DataTypeString>(), std::make_shared<DataTypeString>())},
    };
}

StorageSystemNamedCollections::StorageSystemNamedCollections(const StorageID & table_id_)
    : IStorageSystemOneBlock(table_id_)
{
}

void StorageSystemNamedCollections::fillData(MutableColumns & res_columns, ContextPtr context, const SelectQueryInfo &) const
{
    context->checkAccess(AccessType::SHOW_NAMED_COLLECTIONS);

    auto collections = NamedCollectionFactory::instance().getAll();

    for (const auto & [name, collection] : collections)
    {
        res_columns[0]->insert(name);

        auto * column_map = typeid_cast<ColumnMap *>(res_columns[1].get());

        auto & offsets = column_map->getNestedColumn().getOffsets();
        auto & tuple_column = column_map->getNestedData();
        auto & key_column = tuple_column.getColumn(0);
        auto & value_column = tuple_column.getColumn(1);

        size_t size = 0;
        for (const auto & [key, value] : collection->dumpStructure())
        {
            key_column.insertData(key.data(), key.size());
            value_column.insert(convertFieldToString(value));
            size++;
        }

        offsets.push_back(offsets.back() + size);
    }
}

}