15.1.10 ALTER TABLESPACE Statement

ALTER [UNDO] TABLESPACE tablespace_name
  NDB only:
    {ADD | DROP} DATAFILE 'file_name'
    [INITIAL_SIZE [=] size]
    [WAIT]
  InnoDB and NDB:
    [RENAME TO tablespace_name]
  InnoDB only:
    [AUTOEXTEND_SIZE [=] 'value']
    [SET {ACTIVE | INACTIVE}]
    [ENCRYPTION [=] {'Y' | 'N'}]
  InnoDB and NDB:
    [ENGINE [=] engine_name]
  Reserved for future use:
    [ENGINE_ATTRIBUTE [=] 'string']

This statement is used with NDB and InnoDB tablespaces. It can be used to add a new data file to, or to drop a data file from an NDB tablespace. It can also be used to rename an NDB Cluster Disk Data tablespace, rename an InnoDB general tablespace, encrypt an InnoDB general tablespace, or mark an InnoDB undo tablespace as active or inactive.

The UNDO keyword is used with the SET {ACTIVE | INACTIVE} clause to mark an InnoDB undo tablespace as active or inactive. For more information, see Section 17.6.3.4, “Undo Tablespaces”.

The ADD DATAFILE variant enables you to specify an initial size for an NDB Disk Data tablespace using an INITIAL_SIZE clause, where size is measured in bytes; the default value is 134217728 (128 MB). You may optionally follow size with a one-letter abbreviation for an order of magnitude, similar to those used in my.cnf. Generally, this is one of the letters M (megabytes) or G (gigabytes).

On 32-bit systems, the maximum supported value for INITIAL_SIZE is 4294967296 (4 GB). (Bug #29186)

INITIAL_SIZE is rounded, explicitly, as for CREATE TABLESPACE.

Once a data file has been created, its size cannot be changed; however, you can add more data files to an NDB tablespace using additional ALTER TABLESPACE ... ADD DATAFILE statements.

When ALTER TABLESPACE ... ADD DATAFILE is used with ENGINE = NDB, a data file is created on each Cluster data node, but only one row is generated in the Information Schema FILES table. See the description of this table, as well as Section 25.6.11.1, “NDB Cluster Disk Data Objects”, for more information. ADD DATAFILE is not supported with InnoDB tablespaces.

Using DROP DATAFILE with ALTER TABLESPACE drops the data file 'file_name' from an NDB tablespace. You cannot drop a data file from a tablespace which is in use by any table; in other words, the data file must be empty (no extents used). See Section 25.6.11.1, “NDB Cluster Disk Data Objects”. In addition, any data file to be dropped must previously have been added to the tablespace with CREATE TABLESPACE or ALTER TABLESPACE. DROP DATAFILE is not supported with InnoDB tablespaces.

WAIT is parsed but otherwise ignored. It is intended for future expansion.

The ENGINE clause, which specifies the storage engine used by the tablespace, is deprecated, since the tablespace storage engine is known by the data dictionary, making the ENGINE clause obsolete. In MySQL 8.4, it is supported in the following two cases only:

• ALTER TABLESPACE tablespace_name ADD DATAFILE 'file_name'
      ENGINE={NDB|NDBCLUSTER}

• ALTER UNDO TABLESPACE tablespace_name SET {ACTIVE|INACTIVE}
      ENGINE=INNODB

You should expect the eventual removal of ENGINE from these statements as well, in a future version of MySQL.

RENAME TO operations are implicitly performed in autocommit mode, regardless of the value of autocommit.

A RENAME TO operation cannot be performed while LOCK TABLES or FLUSH TABLES WITH READ LOCK is in effect for tables that reside in the tablespace.

Exclusive metadata locks are taken on tables that reside in a general tablespace while the tablespace is renamed, which prevents concurrent DDL. Concurrent DML is supported.

The CREATE TABLESPACE privilege is required to rename an InnoDB general tablespace.

The AUTOEXTEND_SIZE option defines the amount by which InnoDB extends the size of a tablespace when it becomes full. The setting must be a multiple of 4MB. The default setting is 0, which causes the tablespace to be extended according to the implicit default behavior. For more information, see Section 17.6.3.9, “Tablespace AUTOEXTEND_SIZE Configuration”.

The ENCRYPTION clause enables or disables page-level data encryption for an InnoDB general tablespace or the mysql system tablespace.

A keyring plugin must be installed and configured before encryption can be enabled.

If the table_encryption_privilege_check variable is enabled, the TABLE_ENCRYPTION_ADMIN privilege is required to alter a general tablespace with an ENCRYPTION clause setting that differs from the default_table_encryption setting.

Enabling encryption for a general tablespace fails if any table in the tablespace belongs to a schema defined with DEFAULT ENCRYPTION='N'. Similarly, disabling encryption fails if any table in the general tablespace belongs to a schema defined with DEFAULT ENCRYPTION='Y'.

If an ALTER TABLESPACE statement executed on a general tablespace does not include an ENCRYPTION clause, the tablespace retains its current encryption status, regardless of the default_table_encryption setting.

When a general tablespace or the mysql system tablespace is encrypted, all tables residing in the tablespace are encrypted. Likewise, a table created in an encrypted tablespace is encrypted.

The INPLACE algorithm is used when altering the ENCRYPTION attribute of a general tablespace or the mysql system tablespace. The INPLACE algorithm permits concurrent DML on tables that reside in the tablespace. Concurrent DDL is blocked.

For more information, see Section 17.13, “InnoDB Data-at-Rest Encryption”.

The ENGINE_ATTRIBUTE option is used to specify tablespace attributes for primary storage engines. The option is reserved for future use.

The value assigned to this option is a string literal containing a valid JSON document or an empty string (''). Invalid JSON is rejected.

ALTER TABLESPACE ts1 ENGINE_ATTRIBUTE='{"key":"value"}';

ENGINE_ATTRIBUTE values can be repeated without error. In this case, the last specified value is used.

ENGINE_ATTRIBUTE values are not checked by the server, nor are they cleared when the table's storage engine is changed.

It is not permitted to alter an individual element of a JSON attribute value. You can only add or replace an attribute.