Method doCreateOrReplaceTable

src/Interpreters/InterpreterCreateQuery.cpp:2236–2385

BlockIO InterpreterCreateQuery::doCreateOrReplaceTable(ASTCreateQuery & create,
                                                       const InterpreterCreateQuery::TableProperties & properties, LoadingStrictnessLevel mode)
{
    /// Replicated database requires separate contexts for each DDL query
    ContextPtr current_context = getContext();
    if (auto txn = current_context->getZooKeeperMetadataTransaction())
        txn->setIsCreateOrReplaceQuery();
    ContextMutablePtr create_context = Context::createCopy(current_context);
    create_context->setQueryContext(std::const_pointer_cast<Context>(current_context));

    /// Before actually creating/replacing the table, check if it will lead to cyclic dependencies.
    checkTableCanBeAddedWithNoCyclicDependencies(create, query_ptr, create_context);

    auto make_drop_context = [&]() -> ContextMutablePtr
    {
        ContextMutablePtr drop_context = Context::createCopy(current_context);
        drop_context->setQueryContext(std::const_pointer_cast<Context>(current_context));
        return drop_context;
    };

    auto ast_drop = make_intrusive<ASTDropQuery>();
    String table_to_replace_name = create.getTable();

    {
        auto database = DatabaseCatalog::instance().getDatabase(create.getDatabase());
        if (database->getUUID() == UUIDHelpers::Nil)
            throw Exception(ErrorCodes::INCORRECT_QUERY,
                            "{} query is supported only for Atomic databases",
                            create.create_or_replace
                ? (create.is_materialized_view ? "CREATE OR REPLACE MATERIALIZED VIEW"
                    : (create.isView() ? "CREATE OR REPLACE VIEW" : "CREATE OR REPLACE TABLE"))
                : "REPLACE TABLE");

        if (mode <= LoadingStrictnessLevel::CREATE)
            database->checkTableNameLength(table_to_replace_name);
    }

    {
        const String name_hash = TemporaryReplaceTableName::calculateHash(create.getDatabase(), create.getTable());
        const String random_suffix = [&]()
        {
            if (auto txn = current_context->getZooKeeperMetadataTransaction())
            {
                /// Avoid different table name on database replicas
                UInt64 hashed_zk_path = sipHash64(txn->getTaskZooKeeperPath());
                return getHexUIntLowercase(hashed_zk_path);
            }
            if (!current_context->getCurrentQueryId().empty())
            {
                const UInt32 hashed_query_id = static_cast<UInt32>(sipHash64(current_context->getCurrentQueryId()));
                return getRandomASCIIString(/*length=*/8) + getHexUIntLowercase(hashed_query_id);
            }
            return getRandomASCIIString(/*length=*/16);
        }();

        const String tmp_replace_table_name = TemporaryReplaceTableName{.name_hash = name_hash, .random_suffix = random_suffix}.toString();
        create.setTable(tmp_replace_table_name);