BlockIO InterpreterCreateQuery::createTable(ASTCreateQuery & create)
{
if (!create.cluster.empty())
{
NameSet databases{create.database};
if (!create.to_table.empty())
databases.emplace(create.to_database);
return executeDDLQueryOnCluster(query_ptr, context, std::move(databases));
}
String path = context.getPath();
String current_database = context.getCurrentDatabase();
String database_name = create.database.empty() ? current_database : create.database;
String table_name = create.table;
String table_name_escaped = escapeForFileName(table_name);
// If this is a stub ATTACH query, read the query definition from the database
if (create.attach && !create.storage && !create.columns)
{
// Table SQL definition is available even if the table is detached
auto query = context.getCreateTableQuery(database_name, table_name);
auto & as_create = typeid_cast<const ASTCreateQuery &>(*query);
create = as_create; // Copy the saved create query, but use ATTACH instead of CREATE
create.attach = true;
}
if (create.to_database.empty())
create.to_database = current_database;
if (create.select && (create.is_view || create.is_materialized_view))
{
AddDefaultDatabaseVisitor visitor(current_database);
visitor.visit(*create.select);
}
Block as_select_sample;
if (create.select && (!create.attach || !create.columns))
as_select_sample = InterpreterSelectWithUnionQuery::getSampleBlock(create.select->clone(), context);
String as_database_name = create.as_database.empty() ? current_database : create.as_database;
String as_table_name = create.as_table;
StoragePtr as_storage;
TableStructureReadLockPtr as_storage_lock;
if (!as_table_name.empty())
{
as_storage = context.getTable(as_database_name, as_table_name);
as_storage_lock = as_storage->lockStructure(false);
}
/// Set and retrieve list of columns.
ColumnsDescription columns = setColumns(create, as_select_sample, as_storage);
/// Some column types may be not allowed according to settings.
if (!create.attach)
checkSupportedTypes(columns, context);
/// Set the table engine if it was not specified explicitly.
setEngine(create);
StoragePtr res;
{
std::unique_ptr<DDLGuard> guard;
String data_path;
DatabasePtr database;
if (!create.temporary)
{
database = context.getDatabase(database_name);
data_path = database->getDataPath();
/** If the request specifies IF NOT EXISTS, we allow concurrent CREATE queries (which do nothing).
* If table doesnt exist, one thread is creating table, while others wait in DDLGuard.
*/
guard = context.getDDLGuard(database_name, table_name);
/// Table can be created before or it can be created concurrently in another thread, while we were waiting in DDLGuard.
if (database->isTableExist(context, table_name))
{
if (create.if_not_exists)
return {};
else
throw Exception("Table " + database_name + "." + table_name + " already exists.", ErrorCodes::TABLE_ALREADY_EXISTS);
}
}
else if (context.tryGetExternalTable(table_name) && create.if_not_exists)
return {};
res = StorageFactory::instance().get(create,
data_path,
table_name,
database_name,
context,
context.getGlobalContext(),
columns,
create.attach,
false);
if (create.temporary)
context.getSessionContext().addExternalTable(table_name, res, query_ptr);
else
database->createTable(context, table_name, res, query_ptr);
/// We must call "startup" and "shutdown" while holding DDLGuard.
/// Because otherwise method "shutdown" (from InterpreterDropQuery) can be called before startup
/// (in case when table was created and instantly dropped before started up)
///
/// Method "startup" may create background tasks and method "shutdown" will wait for them.
/// But if "shutdown" is called before "startup", it will exit early, because there are no background tasks to wait.
/// Then background task is created by "startup" method. And when destructor of a table object is called, background task is still active,
/// and the task will use references to freed data.
res->startup();
}
/// If the query is a CREATE SELECT, insert the data into the table.
if (create.select && !create.attach
&& !create.is_view && (!create.is_materialized_view || create.is_populate))
{
auto insert = std::make_shared<ASTInsertQuery>();
if (!create.temporary)
insert->database = database_name;
insert->table = table_name;
insert->select = create.select->clone();
if (create.temporary && !context.getSessionContext().hasQueryContext())
context.getSessionContext().setQueryContext(context.getSessionContext());
return InterpreterInsertQuery(insert,
create.temporary ? context.getSessionContext() : context,
context.getSettingsRef().insert_allow_materialized_columns).execute();
}
return {};
}
BlockIO InterpreterCreateQuery::createTable(ASTCreateQuery & create)
{
if (!create.cluster.empty())
{
NameSet databases{create.database};
if (!create.to_table.empty())
databases.emplace(create.to_database);
return executeDDLQueryOnCluster(query_ptr, context, databases);
}
String path = context.getPath();
String current_database = context.getCurrentDatabase();
String database_name = create.database.empty() ? current_database : create.database;
String table_name = create.table;
String table_name_escaped = escapeForFileName(table_name);
// If this is a stub ATTACH query, read the query definition from the database
if (create.attach && !create.storage && !create.columns)
{
// Table SQL definition is available even if the table is detached
auto query = context.getCreateTableQuery(database_name, table_name);
auto & as_create = typeid_cast<const ASTCreateQuery &>(*query);
create = as_create; // Copy the saved create query, but use ATTACH instead of CREATE
create.attach = true;
}
if (create.to_database.empty())
create.to_database = current_database;
if (create.select && (create.is_view || create.is_materialized_view))
create.select->setDatabaseIfNeeded(current_database);
Block as_select_sample;
if (create.select && (!create.attach || !create.columns))
as_select_sample = InterpreterSelectWithUnionQuery::getSampleBlock(create.select->clone(), context);
String as_database_name = create.as_database.empty() ? current_database : create.as_database;
String as_table_name = create.as_table;
StoragePtr as_storage;
TableStructureReadLockPtr as_storage_lock;
if (!as_table_name.empty())
{
as_storage = context.getTable(as_database_name, as_table_name);
as_storage_lock = as_storage->lockStructure(false, __PRETTY_FUNCTION__);
}
/// Set and retrieve list of columns.
ColumnsDescription columns = setColumns(create, as_select_sample, as_storage);
/// Set the table engine if it was not specified explicitly.
setEngine(create);
StoragePtr res;
{
std::unique_ptr<DDLGuard> guard;
String data_path;
DatabasePtr database;
if (!create.is_temporary)
{
database = context.getDatabase(database_name);
data_path = database->getDataPath();
/** If the table already exists, and the request specifies IF NOT EXISTS,
* then we allow concurrent CREATE queries (which do nothing).
* Otherwise, concurrent queries for creating a table, if the table does not exist,
* can throw an exception, even if IF NOT EXISTS is specified.
*/
guard = context.getDDLGuardIfTableDoesntExist(database_name, table_name,
"Table " + database_name + "." + table_name + " is creating or attaching right now");
if (!guard)
{
if (create.if_not_exists)
return {};
else
throw Exception("Table " + database_name + "." + table_name + " already exists.", ErrorCodes::TABLE_ALREADY_EXISTS);
}
}
else if (context.tryGetExternalTable(table_name) && create.if_not_exists)
return {};
res = StorageFactory::instance().get(create,
data_path,
table_name,
database_name,
context,
context.getGlobalContext(),
columns,
create.attach,
false);
if (create.is_temporary)
context.getSessionContext().addExternalTable(table_name, res, query_ptr);
else
database->createTable(context, table_name, res, query_ptr);
}
res->startup();
/// If the query is a CREATE SELECT, insert the data into the table.
if (create.select && !create.attach
&& !create.is_view && (!create.is_materialized_view || create.is_populate))
{
auto insert = std::make_shared<ASTInsertQuery>();
if (!create.is_temporary)
insert->database = database_name;
insert->table = table_name;
insert->select = create.select->clone();
return InterpreterInsertQuery(insert,
create.is_temporary ? context.getSessionContext() : context,
context.getSettingsRef().insert_allow_materialized_columns).execute();
}
return {};
}
