SELECT @@innodb_undo_tablespaces;
@@innodb_undo_tablespaces
6
use information_schema;
select * from INNODB_TABLESPACES where space >= 4294967276 and space <= 4294967279;
SPACE	NAME	FLAG	ROW_FORMAT	PAGE_SIZE	ZIP_PAGE_SIZE	SPACE_TYPE	FS_BLOCK_SIZE	FILE_SIZE	ALLOCATED_SIZE	SERVER_VERSION	SPACE_VERSION	ENCRYPTION	STATE
4294967279	innodb_undo_001	0	Undo	16384	0	Undo	0	0	0	8.0.18	1	N	active
4294967278	innodb_undo_002	0	Undo	16384	0	Undo	0	0	0	8.0.18	1	N	active
4294967277	innodb_undo_003	0	Undo	16384	0	Undo	0	0	0	8.0.18	1	N	active
4294967276	innodb_undo_004	0	Undo	16384	0	Undo	0	0	0	8.0.18	1	N	active
select * from INNODB_TABLESPACES_BRIEF where space >= 4294967276 and space <= 4294967279;
SPACE	NAME	PATH	FLAG	SPACE_TYPE
4294967279	innodb_undo_001	./undo_001	0	Single
4294967278	innodb_undo_002	./undo_002	0	Single
4294967277	innodb_undo_003	./undo_003	0	Single
4294967276	innodb_undo_004	./undo_004	0	Single
select * from INNODB_DATAFILES where space >= 4294967276 and space <= 4294967279;
SPACE	PATH
4294967279	./undo_001
4294967278	./undo_002
4294967277	./undo_003
4294967276	./undo_004
drop tablespace innodb_undo_001;
ERROR 42000: InnoDB: Tablespace names starting with `innodb_` are reserved.
drop tablespace innodb_undo_002;
ERROR 42000: InnoDB: Tablespace names starting with `innodb_` are reserved.
ALTER UNDO TABLESPACE innodb_undo_001 SET INACTIVE;
ERROR 42000: Cannot ALTER LIZARD TRANSACTION TABLESPACE `innodb_undo_001` because it is a permanent active tablespace.
ALTER UNDO TABLESPACE innodb_undo_002 SET INACTIVE;
ERROR 42000: Cannot ALTER LIZARD TRANSACTION TABLESPACE `innodb_undo_002` because it is a permanent active tablespace.