Tablespaces Space is not released back to the operating system as it is when a file-per-table tablespace is deleted during a  DROP TABLE  operation. This example demonstrates how to drop an  InnoDB  general tablespace. The general tablespace  ts1  is created with a single table. The table must be dropped before dropping the tablespace. mysql>  CREATE TABLESPACE ‘ts1‘ ADD DATAFILE ’ts1.ibd’ Engine=InnoDB; mysql>  CREATE TABLE t1 (c1 INT PRIMARY KEY) TABLESPACE ts1 Engine=InnoDB; mysql>  DROP TABLE t1; mysql>  DROP TABLESPACE ts1; Note tablespace_name  is a case-sensitive identifier in MySQL. General Tablespace Limitations •A generated or existing tablespace cannot be changed to a general tablespace. •Creation of temporary general tablespaces is not supported. •General tablespaces do not support temporary tables. •Similar to the system tablespace, truncating or dropping tables stored in a general tablespace creates free space internally in the general tablespace .ibd data file which can only be used for new  InnoDB data. Space is not released back to the operating system as it is for file-per-table tablespaces. • ALTER TABLE ... DISCARD TABLESPACE  and  ALTER TABLE ...IMPORT TABLESPACE  are not supported for tables that belong to a general tablespace. •Support for placing table partitions in general tablespaces was deprecated in MySQL 5.7.24 and removed in MySQL 8.0.13. •The  ADD DATAFILE  clause is not supported in a replication environment where the source and replica reside on the same host, as it would cause the source and replica to create a tablespace of the same name in the same location, which is not supported. However, if the  ADD DATAFILE  clause is omitted, the tablespace is created in the data directory with a generated file name that is unique, which is permitted. •As of MySQL 8.0.21, general tablespaces cannot be created in the undo tablespace directory ( innodb_undo_directory ) unless that directly is known to  InnoDB . Known directories are those defined by the  datadir ,  innodb_data_home_dir , and  innodb_directories  variables. Additionally, a table-copying  ALTER TABLE  operation on table that resides in a shared tablespace (a general tablespace or the system tablespace) can increase the amount of space used by the tablespace. Such operations require as much additional space as the data in the table plus indexes. The additional space required for the table-copying  ALTER TABLE  operation is not released back to the operating system as it is for file-per-table tablespaces. Undo tablespaces contain undo logs, which are collections of records containing information about how to undo the latest change by a transaction to a clustered index record. Undo tablespaces are described under the following topics in this section: 15.6.3.4 Undo Tablespaces 3059