Method elementDatabaseAndTable

src/Interpreters/InterpreterExplainQuery.cpp:377–403

void InterpreterExplainQuery::elementDatabaseAndTable(const ASTSelectQuery & select_query, const ASTPtr & where, WriteBuffer & buffer)
{
    if (!select_query.tables())
        throw Exception("Can not get database and table in element query", ErrorCodes::LOGICAL_ERROR);

    if (select_query.tables()->children.size() != 1)
        throw Exception("Element query not support multiple table query, such as join, etc", ErrorCodes::LOGICAL_ERROR);

    auto database_and_table = getDatabaseAndTable(select_query, 0);
    if (database_and_table)
    {
        StoragePtr storage = DatabaseCatalog::instance().getTable({database_and_table->database, database_and_table->table}, getContext());
        buffer << "\"database\": \"" << storage->getStorageID().getDatabaseName() << "\", ";
        buffer << "\"table\": \"" << storage->getStorageID().getTableName() << "\", ";
        auto dependencies = DatabaseCatalog::instance().getDependencies(storage->getStorageID());
        buffer << "\"dependencies\": [";
        for (size_t i = 0, size = dependencies.size(); i < size; ++i)
            buffer << "\"" << dependencies[i].getDatabaseName() << "." << dependencies[i].getTableName() << "\""
                   << (i + 1 != size ? ", " : "");
        buffer << "], ";

        listPartitionKeys(storage, buffer);
        listRowsOfOnePartition(storage, select_query.groupBy(), where, buffer);
    }
    else
        throw Exception("Can not get database and table in element query", ErrorCodes::LOGICAL_ERROR);
}

void InterpreterExplainQuery::listPartitionKeys(StoragePtr & storage, WriteBuffer & buffer)
{