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13.1.21 CREATE TABLESPACE Syntax

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  1. CREATE [UNDO] TABLESPACE tablespace_name
  2.  
  3.   InnoDB and NDB:
  4.     [ADD DATAFILE 'file_name']
  5.  
  6.   InnoDB only:
  7.     [FILE_BLOCK_SIZE = value]
  8.     [ENCRYPTION [=] {'Y' | 'N'}]
  9.  
  10.   NDB only:
  11.     USE LOGFILE GROUP logfile_group
  12.     [EXTENT_SIZE [=] extent_size]
  13.     [INITIAL_SIZE [=] initial_size]
  14.     [AUTOEXTEND_SIZE [=] autoextend_size]
  15.     [MAX_SIZE [=] max_size]
  16.     [NODEGROUP [=] nodegroup_id]
  17.     [WAIT]
  18.     [COMMENT [=] 'string']
  19.  
  20.   InnoDB and NDB:
  21.     [ENGINE [=] engine_name]

This statement is used to create a tablespace. The precise syntax and semantics depend on the storage engine used. In standard MySQL releases, this is always an InnoDB tablespace. MySQL NDB Cluster also supports tablespaces using the NDB storage engine.

Considerations for InnoDB

CREATE TABLESPACE syntax is used to create general tablespaces or undo tablespaces. The UNDO keyword, introduced in MySQL 8.0.14, must be specified to create an undo tablespace.

A general tablespace is a shared tablespace. It can hold multiple tables, and supports all table row formats. General tablespaces can be created in a location relative to or independent of the data directory.

After creating an InnoDB general tablespace, use CREATE TABLE tbl_name ... TABLESPACE [=] tablespace_name or ALTER TABLE tbl_name TABLESPACE [=] tablespace_name to add tables to the tablespace. For more information, see Section 15.6.3.3, “General Tablespaces”.

Undo tablespaces contain undo logs. Undo tablespaces can be created in a chosen location by specifying a fully qualified data file path. For more information, see Section 15.6.3.4, “Undo Tablespaces”.

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Considerations for NDB Cluster

This statement is used to create a tablespace, which can contain one or more data files, providing storage space for NDB Cluster Disk Data tables (see Section 22.5.13, “NDB Cluster Disk Data Tables”). One data file is created and added to the tablespace using this statement. Additional data files may be added to the tablespace by using the ALTER TABLESPACE statement (see Section 13.1.10, “ALTER TABLESPACE Syntax”).

Note

All NDB Cluster Disk Data objects share the same namespace. This means that each Disk Data object must be uniquely named (and not merely each Disk Data object of a given type). For example, you cannot have a tablespace and a log file group with the same name, or a tablespace and a data file with the same name.

A log file group of one or more UNDO log files must be assigned to the tablespace to be created with the USE LOGFILE GROUP clause. logfile_group must be an existing log file group created with CREATE LOGFILE GROUP (see Section 13.1.16, “CREATE LOGFILE GROUP Syntax”). Multiple tablespaces may use the same log file group for UNDO logging.

When setting EXTENT_SIZE or INITIAL_SIZE, you may optionally follow the number 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 (for megabytes) or G (for gigabytes).

INITIAL_SIZE and EXTENT_SIZE are subject to rounding as follows:

  • EXTENT_SIZE is rounded up to the nearest whole multiple of 32K.

  • INITIAL_SIZE is rounded down to the nearest whole multiple of 32K; this result is rounded up to the nearest whole multiple of EXTENT_SIZE (after any rounding).

The rounding just described is done explicitly, and a warning is issued by the MySQL Server when any such rounding is performed. The rounded values are also used by the NDB kernel for calculating INFORMATION_SCHEMA.FILES column values and other purposes. However, to avoid an unexpected result, we suggest that you always use whole multiples of 32K in specifying these options.

When CREATE TABLESPACE is used with ENGINE [=] NDB, a tablespace and associated data file are created on each Cluster data node. You can verify that the data files were created and obtain information about them by querying the INFORMATION_SCHEMA.FILES table. (See the example later in this section.)

(See Section 25.11, “The INFORMATION_SCHEMA FILES Table”.)

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Options

  • ADD DATAFILE: Defines the name of a tablespace data file. The ADD DATAFILE clause is required when creating undo tablespaces. Otherwise, it is optional as of MySQL 8.0.14.

    An InnoDB tablespace supports only a single data file, whose name must include a .ibd extension. An NDB Cluster tablespace supports multiple data files which can have any legal file names; more data files can be added to an NDB Cluster tablespace following its creation by using an ALTER TABLESPACE statement.

    To place a general tablespace data file in a location outside of the data directory, include a fully qualified path or a path relative to the data directory. Only a fully qualified path is permitted for undo tablespaces. If you do not specify a path, a general tablespace is created in the data directory. An undo tablespace created without specifying a path is created in the directory defined by the innodb_undo_directory variable. If the innodb_undo_directory variable is undefined, undo tablespaces are created in the data directory.

    Creating a general tablespace in a subdirectory under the data directory is not supported to avoid conflicts with implicitly created file-per-table tablespaces. When creating a general tablespace or undo tablespace outside of the data directory, the directory must exist and must be known to InnoDB prior to creating the tablespace. To make a directory known to InnoDB, add it to the innodb_directories value or to one of the variables whose values are appended to the innodb_directories value. innodb_directories is a read-only variable. Configuring it requires restarting the server.

    The file_name, including any specified path, must be quoted with single or double quotations marks. File names (not counting the file extension) and directory names must be at least one byte in length. Zero length file names and directory names are not supported.

    If the ADD DATAFILE clause is not specified when creating a tablespace, a tablespace data file with a unique file name is created implicitly. The unique file name is a 128 bit UUID formatted into five groups of hexadecimal numbers separated by dashes (aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee). A file extension is added if required by the storage engine. An .ibd file extension is added for InnoDB general tablespace data files. In a replication environment, the data file name created on the master is not the same as the data file name created on the slave.

    As of MySQL 8.0.17, the ADD DATAFILE clause does not permit circular directory references when creating an InnoDB tablespace. For example, the circular directory reference (/../) in the following statement is not permitted:

    1. CREATE TABLESPACE ts1 ADD DATAFILE ts1.ibd 'any_directory/../ts1.ibd';

    An exception to this restriction exists on Linux, where a circular directory reference is permitted if the preceding directory is a symbolic link. For example, the data file path in the example above is permitted if any_directory is a symbolic link. (It is still permitted for data file paths to begin with '../'.)

  • FILE_BLOCK_SIZE: This option—which is specific to InnoDB general tablespaces, and is ignored by NDB—defines the block size for the tablespace data file. Values can be specified in bytes or kilobytes. For example, an 8 kilobyte file block size can be specified as 8192 or 8K. If you do not specify this option, FILE_BLOCK_SIZE defaults to the innodb_page_size value. FILE_BLOCK_SIZE is required when you intend to use the tablespace for storing compressed InnoDB tables (ROW_FORMAT=COMPRESSED). In this case, you must define the tablespace FILE_BLOCK_SIZE when creating the tablespace.

    If FILE_BLOCK_SIZE is equal the innodb_page_size value, the tablespace can contain only tables having an uncompressed row format (COMPACT, REDUNDANT, and DYNAMIC). Tables with a COMPRESSED row format have a different physical page size than uncompressed tables. Therefore, compressed tables cannot coexist in the same tablespace as uncompressed tables.

    For a general tablespace to contain compressed tables, FILE_BLOCK_SIZE must be specified, and the FILE_BLOCK_SIZE value must be a valid compressed page size in relation to the innodb_page_size value. Also, the physical page size of the compressed table (KEY_BLOCK_SIZE) must be equal to FILE_BLOCK_SIZE/1024. For example, if innodb_page_size=16K, and FILE_BLOCK_SIZE=8K, the KEY_BLOCK_SIZE of the table must be 8. For more information, see Section 15.6.3.3, “General Tablespaces”.

  • USE LOGFILE GROUP: Required for NDB, this is the name of a log file group previously created using CREATE LOGFILE GROUP. Not supported for InnoDB, where it fails with an error.

  • EXTENT_SIZE: This option is specific to NDB, and is not supported by InnoDB, where it fails with an error. EXTENT_SIZE sets the size, in bytes, of the extents used by any files belonging to the tablespace. The default value is 1M. The minimum size is 32K, and theoretical maximum is 2G, although the practical maximum size depends on a number of factors. In most cases, changing the extent size does not have any measurable effect on performance, and the default value is recommended for all but the most unusual situations.

    An extent is a unit of disk space allocation. One extent is filled with as much data as that extent can contain before another extent is used. In theory, up to 65,535 (64K) extents may used per data file; however, the recommended maximum is 32,768 (32K). The recommended maximum size for a single data file is 32G—that is, 32K extents × 1 MB per extent. In addition, once an extent is allocated to a given partition, it cannot be used to store data from a different partition; an extent cannot store data from more than one partition. This means, for example that a tablespace having a single datafile whose INITIAL_SIZE (described in the following item) is 256 MB and whose EXTENT_SIZE is 128M has just two extents, and so can be used to store data from at most two different disk data table partitions.

    You can see how many extents remain free in a given data file by querying the INFORMATION_SCHEMA.FILES table, and so derive an estimate for how much space remains free in the file. For further discussion and examples, see Section 25.11, “The INFORMATION_SCHEMA FILES Table”.

  • INITIAL_SIZE: This option is specific to NDB, and is not supported by InnoDB, where it fails with an error.

    The INITIAL_SIZE parameter sets the total size in bytes of the data file that was specific using ADD DATATFILE. Once this file has been created, its size cannot be changed; however, you can add more data files to the tablespace using ALTER TABLESPACE ... ADD DATAFILE.

    INITIAL_SIZE is optional; its default value is 134217728 (128 MB).

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

  • AUTOEXTEND_SIZE: Currently ignored by MySQL; reserved for possible future use. Has no effect in any release of MySQL 8.0 or MySQL NDB Cluster 8.0, regardless of the storage engine used.

  • MAX_SIZE: Currently ignored by MySQL; reserved for possible future use. Has no effect in any release of MySQL 8.0 or MySQL NDB Cluster 8.0, regardless of the storage engine used.

  • NODEGROUP: Currently ignored by MySQL; reserved for possible future use. Has no effect in any release of MySQL 8.0 or MySQL NDB Cluster 8.0, regardless of the storage engine used.

  • WAIT: Currently ignored by MySQL; reserved for possible future use. Has no effect in any release of MySQL 8.0 or MySQL NDB Cluster 8.0, regardless of the storage engine used.

  • COMMENT: Currently ignored by MySQL; reserved for possible future use. Has no effect in any release of MySQL 8.0 or MySQL NDB Cluster 8.0, regardless of the storage engine used.

  • The ENCRYPTION clause enables or disables page-level data encryption for an InnoDB general tablespace. Encryption support for general tablespaces was introduced in MySQL 8.0.13.

    As of MySQL 8.0.16, if the ENCRYPTION clause is not specified, the default_table_encryption setting controls whether encryption is enabled. The ENCRYPTION clause overrides the default_table_encryption setting. However, if the table_encryption_privilege_check variable is enabled, the TABLE_ENCRYPTION_ADMIN privilege is required to use an ENCRYPTION clause setting that differs from the default_table_encryption setting.

    A keyring plugin must be installed and configured before an encryption-enabled tablespace can be created.

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

    For more information, see Section 15.6.3.9, “InnoDB Data-at-Rest Encryption”

  • ENGINE: Defines the storage engine which uses the tablespace, where engine_name is the name of the storage engine. Currently, only the InnoDB storage engine is supported by standard MySQL 8.0 releases. MySQL NDB Cluster supports both NDB and InnoDB tablespaces. The value of the default_storage_engine system variable is used for ENGINE if the option is not specified.

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Notes

  • For the rules covering the naming of MySQL tablespaces, see Section 9.2, “Schema Object Names”. In addition to these rules, the slash character (“/”) is not permitted, nor can you use names beginning with innodb_, as this prefix is reserved for system use.

  • Creation of temporary general tablespaces is not supported.

  • General tablespaces do not support temporary tables.

  • The TABLESPACE option may be used with CREATE TABLE or ALTER TABLE to assign an InnoDB table partition or subpartition to a file-per-table tablespace. All partitions must belong to the same storage engine. Assigning table partitions to shared InnoDB tablespaces is not supported. Shared tablespaces include the InnoDB system tablespace and general tablespaces.

  • General tablespaces support the addition of tables of any row format using CREATE TABLE ... TABLESPACE. innodb_file_per_table does not need to be enabled.

  • innodb_strict_mode is not applicable to general tablespaces. Tablespace management rules are strictly enforced independently of innodb_strict_mode. If CREATE TABLESPACE parameters are incorrect or incompatible, the operation fails regardless of the innodb_strict_mode setting. When a table is added to a general tablespace using CREATE TABLE ... TABLESPACE or ALTER TABLE ... TABLESPACE, innodb_strict_mode is ignored but the statement is evaluated as if innodb_strict_mode is enabled.

  • Use DROP TABLESPACE to remove a tablespace. All tables must be dropped from a tablespace using DROP TABLE prior to dropping the tablespace. Before dropping an NDB Cluster tablespace you must also remove all its data files using one or more ALTER TABLESPACE ... DROP DATATFILE statements. See Section 22.5.13.1, “NDB Cluster Disk Data Objects”.

  • All parts of an InnoDB table added to an InnoDB general tablespace reside in the general tablespace, including indexes and BLOB pages.

    For an NDB table assigned to a tablespace, only those columns which are not indexed are stored on disk, and actually use the tablespace data files. Indexes and indexed columns for all NDB tables are always kept in memory.

  • 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.

  • A general tablespace is not associated with any database or schema.

  • ALTER TABLE ... DISCARD TABLESPACE and ALTER TABLE ...IMPORT TABLESPACE are not supported for tables that belong to a general tablespace.

  • The server uses tablespace-level metadata locking for DDL that references general tablespaces. By comparison, the server uses table-level metadata locking for DDL that references file-per-table tablespaces.

  • A generated or existing tablespace cannot be changed to a general tablespace.

  • There is no conflict between general tablespace names and file-per-table tablespace names. The “/” character, which is present in file-per-table tablespace names, is not permitted in general tablespace names.

  • mysqldump and mysqlpump do not dump InnoDB CREATE TABLESPACE statements.

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InnoDB Examples

This example demonstrates creating a general tablespace and adding three uncompressed tables of different row formats.

  1. mysql> CREATE TABLESPACE `ts1` ADD DATAFILE 'ts1.ibd' ENGINE=INNODB;
  2.  
  3. mysql> CREATE TABLE t1 (c1 INT PRIMARY KEY) TABLESPACE ts1 ROW_FORMAT=REDUNDANT;
  4.  
  5. mysql> CREATE TABLE t2 (c1 INT PRIMARY KEY) TABLESPACE ts1 ROW_FORMAT=COMPACT;
  6.  
  7. mysql> CREATE TABLE t3 (c1 INT PRIMARY KEY) TABLESPACE ts1 ROW_FORMAT=DYNAMIC;

This example demonstrates creating a general tablespace and adding a compressed table. The example assumes a default innodb_page_size value of 16K. The FILE_BLOCK_SIZE of 8192 requires that the compressed table have a KEY_BLOCK_SIZE of 8.

  1. mysql> CREATE TABLESPACE `ts2` ADD DATAFILE 'ts2.ibd' FILE_BLOCK_SIZE = 8192 Engine=InnoDB;
  2.  
  3. mysql> CREATE TABLE t4 (c1 INT PRIMARY KEY) TABLESPACE ts2 ROW_FORMAT=COMPRESSED KEY_BLOCK_SIZE=8;

This example demonstrates creating a general tablespace without specifying the ADD DATAFILE clause, which is optional as of MySQL 8.0.14.

  1. mysql> CREATE TABLESPACE `ts3` ENGINE=INNODB;

This example demonstrates creating an undo tablespace.

  1. mysql> CREATE UNDO TABLESPACE undo_003 ADD DATAFILE 'undo_003.ibu';

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NDB Example

Suppose that you wish to create an NDB Cluster Disk Data tablespace named myts using a datafile named mydata-1.dat. An NDB tablespace always requires the use of a log file group consisting of one or more undo log files. For this example, we first create a log file group named mylg that contains one undo long file named myundo-1.dat, using the CREATE LOGFILE GROUP statement shown here:

  1. mysql> CREATE LOGFILE GROUP myg1
  2.     ->     ADD UNDOFILE 'myundo-1.dat'
  3.     ->     ENGINE=NDB;
  4. Query OK, 0 rows affected (3.29 sec)

Now you can create the tablespace previously described using the following statement:

  1. mysql> CREATE TABLESPACE myts
  2.     ->     ADD DATAFILE 'mydata-1.dat'
  3.     ->     USE LOGFILE GROUP mylg
  4.     ->     ENGINE=NDB;
  5. Query OK, 0 rows affected (2.98 sec)

You can now create a Disk Data table using a CREATE TABLE statement with the TABLESPACE and STORAGE DISK options, similar to what is shown here:

  1. mysql> CREATE TABLE mytable (
  2.     ->     id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
  3.     ->     lname VARCHAR(50) NOT NULL,
  4.     ->     fname VARCHAR(50) NOT NULL,
  5.     ->     dob DATE NOT NULL,
  6.     ->     joined DATE NOT NULL,
  7.     ->     INDEX(last_name, first_name)
  8.     -> )
  9.     ->     TABLESPACE myts STORAGE DISK
  10.     ->     ENGINE=NDB;
  11. Query OK, 0 rows affected (1.41 sec)

It is important to note that only the dob and joined columns from mytable are actually stored on disk, due to the fact that the id, lname, and fname columns are all indexed.

As mentioned previously, when CREATE TABLESPACE is used with ENGINE [=] NDB, a tablespace and associated data file are created on each NDB Cluster data node. You can verify that the data files were created and obtain information about them by querying the INFORMATION_SCHEMA.FILES table, as shown here:

  1. mysql> SELECT FILE_NAME, FILE_TYPE, LOGFILE_GROUP_NAME, STATUS, EXTRA
  2.     ->     FROM INFORMATION_SCHEMA.FILES
  3.     ->     WHERE TABLESPACE_NAME = 'myts';
  4.  
  5. +--------------+------------+--------------------+--------+----------------+
  6. | file_name    | file_type  | logfile_group_name | status | extra          |
  7. +--------------+------------+--------------------+--------+----------------+
  8. | mydata-1.dat | DATAFILE   | mylg               | NORMAL | CLUSTER_NODE=5 |
  9. | mydata-1.dat | DATAFILE   | mylg               | NORMAL | CLUSTER_NODE=6 |
  10. | NULL         | TABLESPACE | mylg               | NORMAL | NULL           |
  11. +--------------+------------+--------------------+--------+----------------+
  12. 3 rows in set (0.01 sec)

For additional information and examples, see Section 22.5.13.1, “NDB Cluster Disk Data Objects”.


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