BlockIO InterpreterDropQuery::execute()
{
ASTDropQuery & drop = typeid_cast<ASTDropQuery &>(*query_ptr);
checkAccess(drop);
if (!drop.cluster.empty())
return executeDDLQueryOnCluster(query_ptr, context, {drop.database});
if (!drop.table.empty())
return executeToTable(drop.database, drop.table, drop.kind, drop.if_exists, drop.temporary);
else if (!drop.database.empty())
return executeToDatabase(drop.database, drop.kind, drop.if_exists);
else
throw Exception("Database and table names is empty.", ErrorCodes::LOGICAL_ERROR);
}
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 InterpreterAlterQuery::execute()
{
auto & alter = typeid_cast<ASTAlterQuery &>(*query_ptr);
if (!alter.cluster.empty())
return executeDDLQueryOnCluster(query_ptr, context, {alter.table});
const String & table_name = alter.table;
String database_name = alter.database.empty() ? context.getCurrentDatabase() : alter.database;
StoragePtr table = context.getTable(database_name, table_name);
AlterCommands alter_commands;
PartitionCommands partition_commands;
MutationCommands mutation_commands;
parseAlter(alter.parameters, alter_commands, partition_commands, mutation_commands);
if (!mutation_commands.commands.empty())
{
mutation_commands.validate(*table, context);
table->mutate(mutation_commands, context);
}
partition_commands.validate(*table);
for (const PartitionCommand & command : partition_commands)
{
switch (command.type)
{
case PartitionCommand::DROP_PARTITION:
table->dropPartition(query_ptr, command.partition, command.detach, context);
break;
case PartitionCommand::ATTACH_PARTITION:
table->attachPartition(command.partition, command.part, context);
break;
case PartitionCommand::REPLACE_PARTITION:
{
String from_database = command.from_database.empty() ? context.getCurrentDatabase() : command.from_database;
auto from_storage = context.getTable(from_database, command.from_table);
table->replacePartitionFrom(from_storage, command.partition, command.replace, context);
}
break;
case PartitionCommand::FETCH_PARTITION:
table->fetchPartition(command.partition, command.from_zookeeper_path, context);
break;
case PartitionCommand::FREEZE_PARTITION:
table->freezePartition(command.partition, command.with_name, context);
break;
case PartitionCommand::CLEAR_COLUMN:
table->clearColumnInPartition(command.partition, command.column_name, context);
break;
}
}
if (!alter_commands.empty())
{
alter_commands.validate(*table, context);
table->alter(alter_commands, database_name, table_name, context);
}
return {};
}
BlockIO InterpreterCreateQuery::createDatabase(ASTCreateQuery & create)
{
if (!create.cluster.empty())
return executeDDLQueryOnCluster(query_ptr, context, {create.database});
String database_name = create.database;
if (create.if_not_exists && context.isDatabaseExist(database_name))
return {};
String database_engine_name;
if (!create.storage)
{
database_engine_name = "Ordinary"; /// Default database engine.
auto engine = std::make_shared<ASTFunction>();
engine->name = database_engine_name;
auto storage = std::make_shared<ASTStorage>();
storage->set(storage->engine, engine);
create.set(create.storage, storage);
}
else
{
const ASTStorage & storage = *create.storage;
const ASTFunction & engine = *storage.engine;
/// Currently, there are no database engines, that support any arguments.
if (engine.arguments || engine.parameters || storage.partition_by || storage.order_by || storage.sample_by || storage.settings)
{
std::stringstream ostr;
formatAST(storage, ostr, false, false);
throw Exception("Unknown database engine: " + ostr.str(), ErrorCodes::UNKNOWN_DATABASE_ENGINE);
}
database_engine_name = engine.name;
}
String database_name_escaped = escapeForFileName(database_name);
/// Create directories for tables metadata.
String path = context.getPath();
String metadata_path = path + "metadata/" + database_name_escaped + "/";
Poco::File(metadata_path).createDirectory();
DatabasePtr database = DatabaseFactory::get(database_engine_name, database_name, metadata_path, context);
/// Will write file with database metadata, if needed.
String metadata_file_tmp_path = path + "metadata/" + database_name_escaped + ".sql.tmp";
String metadata_file_path = path + "metadata/" + database_name_escaped + ".sql";
bool need_write_metadata = !create.attach;
if (need_write_metadata)
{
create.attach = true;
create.if_not_exists = false;
std::ostringstream statement_stream;
formatAST(create, statement_stream, false);
statement_stream << '\n';
String statement = statement_stream.str();
/// Exclusive flag guarantees, that database is not created right now in another thread.
WriteBufferFromFile out(metadata_file_tmp_path, statement.size(), O_WRONLY | O_CREAT | O_EXCL);
writeString(statement, out);
out.next();
if (context.getSettingsRef().fsync_metadata)
out.sync();
out.close();
}
try
{
context.addDatabase(database_name, database);
if (need_write_metadata)
Poco::File(metadata_file_tmp_path).renameTo(metadata_file_path);
database->loadTables(context, thread_pool, has_force_restore_data_flag);
}
catch (...)
{
if (need_write_metadata)
Poco::File(metadata_file_tmp_path).remove();
throw;
}
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 {};
}