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13.1.10 ALTER TABLESPACE Syntax
- NDB only:
- [INITIAL_SIZE [=] size]
- [WAIT]
- InnoDB only:
- [ENCRYPTION [=] {'Y' | 'N'}]
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, introduced in MySQL 8.0.14,
is used with the SET {ACTIVE|INACTIVE}
clause
to mark an InnoDB
undo tablespace as active or
inactive. For more information, see
Section 15.6.3.4, “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 22.5.13.1, “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 22.5.13.1, “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 and will be removed
in a future release. The tablespace storage engine is known by the
data dictionary, making the ENGINE
clause
obsolete. If the storage engine is specified, it must match the
tablespace storage engine defined in the data dictionary. The only
values for engine_name
compatible with
NDB
tablespaces are
NDB
and NDBCLUSTER
.
RENAME TO
operations are implicitly performed
in autocommit
mode, regardless of
the autocommit
setting.
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 ENCRYPTION
option is used to enable or
disable page-level data encryption for an
InnoDB
general tablespace. Option values are
not case-sensitive. Encryption support for general tablespaces was
introduced in MySQL 8.0.13. A keyring plugin must be installed and
configured to encrypt a tablespace using the
ENCRYPTION
option.
When a general tablespace is encrypted, all tables residing in the tablespace are encrypted. Likewise, a table created in an encrypted general tablespace is encrypted.
The INPLACE
algorithm is used when altering the
ENCRYPTION
attribute of a general tablespace.
The INPLACE
algorithm permits concurrent DML on
tables that reside in the general tablespace. Concurrent DDL is
blocked.
For more information, see Section 15.6.3.9, “Tablespace Encryption”.
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