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MySQL 5.7 Reference Manual  /  ...  /  CREATE TABLESPACE Syntax

14.1.19 CREATE TABLESPACE Syntax

CREATE TABLESPACE tablespace_name

  InnoDB and NDB:
    ADD DATAFILE 'file_name'

  InnoDB only:
    [FILE_BLOCK_SIZE = value]

  NDB only:
    USE LOGFILE GROUP logfile_group
    [EXTENT_SIZE [=] extent_size]
    [INITIAL_SIZE [=] initial_size]
    [AUTOEXTEND_SIZE [=] autoextend_size]
    [MAX_SIZE [=] max_size]
    [NODEGROUP [=] nodegroup_id]
    [WAIT]
    [COMMENT [=] comment_text]

  InnoDB and NDB:
    [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 5.7 releases, this is always an InnoDB tablespace. MySQL Cluster NDB 7.5 also supports tablespaces using the NDB storage engine in addition to those using InnoDB.

Considerations for InnoDB

An InnoDB tablespace created using CREATE TABLESPACE is referred to as a general tablespace. This is a shared tablespace, similar to the system 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 MySQL data directory.

After creating an InnoDB general tablespace, you can 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 15.7.9, “InnoDB General Tablespaces”.

CREATE TABLESPACE is supported with InnoDB as of MySQL 5.7.6.

Considerations for MySQL Cluster (NDB)

This statement is used to create a tablespace, which can contain one or more data files, providing storage space for MySQL Cluster Disk Data tables (see Section 19.5.13, “MySQL 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 14.1.9, “ALTER TABLESPACE Syntax”).

Note

All MySQL 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 14.1.15, “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 22.8, “The INFORMATION_SCHEMA FILES Table”.)

Options

  • ADD DATAFILE: Defines the name of a tablespace data file; this option is always required. An InnoDB tablespace supports only a single data file, whose name must include a .ibd extension. A MySQL Cluster tablespace supports multiple data files which can have any legal file names; more data files can be added to a MySQL Cluster tablespace following its creation by using an ALTER TABLESPACE statement.

    Note

    ALTER TABLESPACE is not supported by InnoDB.

    To place the data file in a location outside of the MySQL data directory (datadir), include an absolute directory path or a path relative to the MySQL data directory. If you do not specify a path, the tablespace is created in the MySQL data directory. As of MySQL 5.7.8, an isl file is created in the MySQL data directory when an InnoDB tablespace is created outside of the MySQL data directory.

    To avoid conflicts with implicitly created file-per-table tablespaces, creating a general tablespace in a subdirectory under the MySQL data directory is not supported. Also, when creating a general tablespace outside of the MySQL data directory, the directory must exist prior to creating the tablespace.

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

  • FILE_BLOCK_SIZE: This option—which is specific to InnoDB, and is ignored by NDB—defines the block size for the tablespace data file. If you do not specify this option, FILE_BLOCK_SIZE defaults to innodb_page_size. FILE_BLOCK_SIZE is required when you intend to use the tablespace for storing compressed InnoDB tables (ROW_FORMAT=COMPRESSED).

    If FILE_BLOCK_SIZE is equal innodb_page_size, the tablespace can contain only tables having an uncompressed row format (COMPACT, REDUNDANT, or DYNAMIC). The physical page size for tables using COMPRESSED differs from that of uncompressed tables; this means that compressed tables and uncompressed tables cannot coexist in the same tablespace.

    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 15.7.9, “InnoDB 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 22.8, “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 5.7 or MySQL Cluster NDB 7.5, 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 5.7 or MySQL Cluster NDB 7.5, regardless of the storage engine used.

  • NODEGROUP: Currently ignored by MySQL; reserved for possible future use. Has no effect in any release of MySQL 5.7 or MySQL Cluster NDB 7.5, regardless of the storage engine used.

  • WAIT: Currently ignored by MySQL; reserved for possible future use. Has no effect in any release of MySQL 5.7 or MySQL Cluster NDB 7.5, regardless of the storage engine used.

  • COMMENT: Currently ignored by MySQL; reserved for possible future use. Has no effect in any release of MySQL 5.7 or MySQL Cluster NDB 7.5, regardless of the storage engine used.

  • 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 5.7 releases. MySQL Cluster NDB 7.5 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.

Notes

  • For the rules covering the naming of MySQL tablespaces, see Section 10.2, “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.

  • Tablespaces do not support temporary tables.

  • As of MySQL 5.7.8, the TABLESPACE option may be used with CREATE TABLE or ALTER TABLE to assign InnoDB table partitions or subpartitions to a general tablespace, a separate file-per-table tablespace, or the system tablespace. TABLESPACE option support for table partitions and subpartitions was added in MySQL 5.7.8. All partitions must belong to the same storage engine. For more information, see Section 15.7.9, “InnoDB General Tablespaces”.

  • innodb_file_per_table, innodb_file_format, and innodb_file_format_max settings have no influence on CREATE TABLESPACE operations. innodb_file_per_table does not need to be enabled. General tablespaces support all table row formats regardless of file format settings. Likewise, general tablespaces support the addition of tables of any row format using CREATE TABLE ... TABLESPACE, regardless of file format settings.

  • 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 a MySQL Cluster tablespace you must also remove all its data files using one or more ALTER TABLESPACE ... DROP DATATFILE statements. See Section 19.5.13.1, “MySQL 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.

  • Tables stored in a general tablespace can only be opened in MySQL 5.7.6 or later due to the addition of new table flags.

  • 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.

  • General tablespaces created on Windows using a relative data file path cannot be opened on Unix-like systems. This limitation is removed in MySQL 5.7.8 (Bug #20555168).

  • In MySQL 5.7.6 and MySQL 5.7.7, tables stored in general tablespaces may not open (due to a missing general tablespace file) after moving the MySQL data directory to a new location. This limitation is addressed in MySQL 5.7.8 with the introduction of isl files for general tablespaces created outside of the MySQL data directory (Bug #20563954).

InnoDB Examples

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

mysql> CREATE TABLESPACE `ts1`
    ->     ADD DATAFILE 'ts1.ibd'
    ->     ENGINE=INNODB;
Query OK, 0 rows affected (0.01 sec)

mysql> CREATE TABLE t1 (c1 INT PRIMARY KEY)
    ->     TABLESPACE ts1
    ->     ROW_FORMAT=REDUNDANT;
Query OK, 0 rows affected (0.00 sec)

mysql> CREATE TABLE t2 (c1 INT PRIMARY KEY)
    ->     TABLESPACE ts1
    ->     ROW_FORMAT=COMPACT;
Query OK, 0 rows affected (0.00 sec)

mysql> CREATE TABLE t3 (c1 INT PRIMARY KEY)
    ->     TABLESPACE ts1
    ->     ROW_FORMAT=DYNAMIC;
Query OK, 0 rows affected (0.00 sec)

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

mysql> CREATE TABLESPACE `ts2`
    ->   ADD DATAFILE 'ts2.ibd'
    ->   FILE_BLOCK_SIZE = 8192
    ->   ENGINE=INNODB;
Query OK, 0 rows affected (0.01 sec)

mysql> CREATE TABLE t4 (c1 INT PRIMARY KEY)
    ->   TABLESPACE ts2
    ->   ROW_FORMAT=COMPRESSED
    ->   KEY_BLOCK_SIZE=8;
Query OK, 0 rows affected (0.00 sec)

NDB Example

Suppose that you wish to create a MySQL 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:

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

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

mysql> CREATE TABLESPACE myts
    ->     ADD DATAFILE 'mydata-1.dat'
    ->     USE LOGFILE GROUP mylg
    ->     ENGINE=NDB;
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:

mysql> CREATE TABLE mytable (
    ->     id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
    ->     lname VARCHAR(50) NOT NULL,
    ->     fname VARCHAR(50) NOT NULL,
    ->     dob DATE NOT NULL,
    ->     joined DATE NOT NULL,
    ->     INDEX(last_name, first_name)
    -> )
    ->     TABLESPACE myts STORAGE DISK
    ->     ENGINE=NDB;
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 MySQL 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:

mysql> SELECT FILE_NAME, FILE_TYPE, LOGFILE_GROUP_NAME, STATUS, EXTRA
    ->     FROM INFORMATION_SCHEMA.FILES
    ->     WHERE TABLESPACE_NAME = 'myts';

+--------------+------------+--------------------+--------+----------------+
| file_name    | file_type  | logfile_group_name | status | extra          |
+--------------+------------+--------------------+--------+----------------+
| mydata-1.dat | DATAFILE   | mylg               | NORMAL | CLUSTER_NODE=5 |
| mydata-1.dat | DATAFILE   | mylg               | NORMAL | CLUSTER_NODE=6 |
| NULL         | TABLESPACE | mylg               | NORMAL | NULL           |
+--------------+------------+--------------------+--------+----------------+
3 rows in set (0.01 sec)

For additional information and examples, see Section 19.5.13.1, “MySQL Cluster Disk Data Objects”.


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