17.9.1.7 SQL Compression Syntax Warnings and Errors

This section describes syntax warnings and errors that you may encounter when using the table compression feature with file-per-table tablespaces and general tablespaces.

SQL Compression Syntax Warnings and Errors for File-Per-Table Tablespaces

When innodb_strict_mode is enabled (the default), specifying ROW_FORMAT=COMPRESSED or KEY_BLOCK_SIZE in CREATE TABLE or ALTER TABLE statements produces the following error if innodb_file_per_table is disabled.

ERROR 1031 (HY000): Table storage engine for 't1' doesn't have this option

Note

The table is not created if the current configuration does not permit using compressed tables.

When innodb_strict_mode is disabled, specifying ROW_FORMAT=COMPRESSED or KEY_BLOCK_SIZE in CREATE TABLE or ALTER TABLE statements produces the following warnings if innodb_file_per_table is disabled.

mysql> SHOW WARNINGS;
+---------+------+---------------------------------------------------------------+
| Level   | Code | Message                                                       |
+---------+------+---------------------------------------------------------------+
| Warning | 1478 | InnoDB: KEY_BLOCK_SIZE requires innodb_file_per_table.        |
| Warning | 1478 | InnoDB: ignoring KEY_BLOCK_SIZE=4.                            |
| Warning | 1478 | InnoDB: ROW_FORMAT=COMPRESSED requires innodb_file_per_table. |
| Warning | 1478 | InnoDB: assuming ROW_FORMAT=DYNAMIC.                          |
+---------+------+---------------------------------------------------------------+

Note

These messages are only warnings, not errors, and the table is created without compression, as if the options were not specified.

The “non-strict” behavior lets you import a mysqldump file into a database that does not support compressed tables, even if the source database contained compressed tables. In that case, MySQL creates the table in ROW_FORMAT=DYNAMIC instead of preventing the operation.

To import the dump file into a new database, and have the tables re-created as they exist in the original database, ensure the server has the proper setting for the innodb_file_per_table configuration parameter.

The attribute KEY_BLOCK_SIZE is permitted only when ROW_FORMAT is specified as COMPRESSED or is omitted. Specifying a KEY_BLOCK_SIZE with any other ROW_FORMAT generates a warning that you can view with SHOW WARNINGS. However, the table is non-compressed; the specified KEY_BLOCK_SIZE is ignored).

Level	Code	Message
Warning	1478	InnoDB: ignoring KEY_BLOCK_SIZE=n unless ROW_FORMAT=COMPRESSED.

If you are running with innodb_strict_mode enabled, the combination of a KEY_BLOCK_SIZE with any ROW_FORMAT other than COMPRESSED generates an error, not a warning, and the table is not created.

Table 17.11, “ROW_FORMAT and KEY_BLOCK_SIZE Options” provides an overview the ROW_FORMAT and KEY_BLOCK_SIZE options that are used with CREATE TABLE or ALTER TABLE.

Table 17.11 ROW_FORMAT and KEY_BLOCK_SIZE Options

Option	Usage Notes	Description
ROW_FORMAT=​REDUNDANT	Storage format used prior to MySQL 5.0.3	Less efficient than ROW_FORMAT=COMPACT; for backward compatibility
ROW_FORMAT=​COMPACT	Default storage format since MySQL 5.0.3	Stores a prefix of 768 bytes of long column values in the clustered index page, with the remaining bytes stored in an overflow page
ROW_FORMAT=​DYNAMIC		Store values within the clustered index page if they fit; if not, stores only a 20-byte pointer to an overflow page (no prefix)
ROW_FORMAT=​COMPRESSED		Compresses the table and indexes using zlib
KEY_BLOCK_​SIZE=n		Specifies compressed page size of 1, 2, 4, 8 or 16 kilobytes; implies ROW_FORMAT=COMPRESSED. For general tablespaces, a KEY_BLOCK_SIZE value equal to the InnoDB page size is not permitted.

Table 17.12, “CREATE/ALTER TABLE Warnings and Errors when InnoDB Strict Mode is OFF” summarizes error conditions that occur with certain combinations of configuration parameters and options on the CREATE TABLE or ALTER TABLE statements, and how the options appear in the output of SHOW TABLE STATUS.

When innodb_strict_mode is OFF, MySQL creates or alters the table, but ignores certain settings as shown below. You can see the warning messages in the MySQL error log. When innodb_strict_mode is ON, these specified combinations of options generate errors, and the table is not created or altered. To see the full description of the error condition, issue the SHOW ERRORS statement: example:

mysql> CREATE TABLE x (id INT PRIMARY KEY, c INT)
    -> ENGINE=INNODB KEY_BLOCK_SIZE=33333;
ERROR 1005 (HY000): Can't create table 'test.x' (errno: 1478)
mysql> SHOW ERRORS;
+-------+------+-------------------------------------------+
| Level | Code | Message                                   |
+-------+------+-------------------------------------------+
| Error | 1478 | InnoDB: invalid KEY_BLOCK_SIZE=33333.     |
| Error | 1005 | Can't create table 'test.x' (errno: 1478) |
+-------+------+-------------------------------------------+

Table 17.12 CREATE/ALTER TABLE Warnings and Errors when InnoDB Strict Mode is OFF

Syntax	Warning or Error Condition	Resulting ROW_FORMAT, as shown in SHOW TABLE STATUS
ROW_FORMAT=REDUNDANT	None	REDUNDANT
ROW_FORMAT=COMPACT	None	COMPACT
ROW_FORMAT=COMPRESSED or ROW_FORMAT=DYNAMIC or KEY_BLOCK_SIZE is specified	Ignored for file-per-table tablespaces unless innodb_file_per_table is enabled. General tablespaces support all row formats. See Section 17.6.3.3, “General Tablespaces”.	the default row format for file-per-table tablespaces; the specified row format for general tablespaces
Invalid KEY_BLOCK_SIZE is specified (not 1, 2, 4, 8 or 16)	KEY_BLOCK_SIZE is ignored	the specified row format, or the default row format
ROW_FORMAT=COMPRESSED and valid KEY_BLOCK_SIZE are specified	None; KEY_BLOCK_SIZE specified is used	COMPRESSED
KEY_BLOCK_SIZE is specified with REDUNDANT, COMPACT or DYNAMIC row format	KEY_BLOCK_SIZE is ignored	REDUNDANT, COMPACT or DYNAMIC
ROW_FORMAT is not one of REDUNDANT, COMPACT, DYNAMIC or COMPRESSED	Ignored if recognized by the MySQL parser. Otherwise, an error is issued.	the default row format or N/A

When innodb_strict_mode is ON, MySQL rejects invalid ROW_FORMAT or KEY_BLOCK_SIZE parameters and issues errors. Strict mode is ON by default. When innodb_strict_mode is OFF, MySQL issues warnings instead of errors for ignored invalid parameters.

It is not possible to see the chosen KEY_BLOCK_SIZE using SHOW TABLE STATUS. The statement SHOW CREATE TABLE displays the KEY_BLOCK_SIZE (even if it was ignored when creating the table). The real compressed page size of the table cannot be displayed by MySQL.

SQL Compression Syntax Warnings and Errors for General Tablespaces

• If FILE_BLOCK_SIZE was not defined for the general tablespace when the tablespace was created, the tablespace cannot contain compressed tables. If you attempt to add a compressed table, an error is returned, as shown in the following example:

  mysql> CREATE TABLESPACE `ts1` ADD DATAFILE 'ts1.ibd' Engine=InnoDB;
  
  mysql> CREATE TABLE t1 (c1 INT PRIMARY KEY) TABLESPACE ts1 ROW_FORMAT=COMPRESSED
         KEY_BLOCK_SIZE=8;
  ERROR 1478 (HY000): InnoDB: Tablespace `ts1` cannot contain a COMPRESSED table

• Attempting to add a table with an invalid KEY_BLOCK_SIZE to a general tablespace returns an error, as shown in the following example:

  mysql> CREATE TABLESPACE `ts2` ADD DATAFILE 'ts2.ibd' FILE_BLOCK_SIZE = 8192 Engine=InnoDB;
  
  mysql> CREATE TABLE t2 (c1 INT PRIMARY KEY) TABLESPACE ts2 ROW_FORMAT=COMPRESSED
         KEY_BLOCK_SIZE=4;
  ERROR 1478 (HY000): InnoDB: Tablespace `ts2` uses block size 8192 and cannot
  contain a table with physical page size 4096

  For general tablespaces, the KEY_BLOCK_SIZE of the table must be equal to the FILE_BLOCK_SIZE of the tablespace divided by 1024. For example, if the FILE_BLOCK_SIZE of the tablespace is 8192, the KEY_BLOCK_SIZE of the table must be 8.

• Attempting to add a table with an uncompressed row format to a general tablespace configured to store compressed tables returns an error, as shown in the following example:

  mysql> CREATE TABLESPACE `ts3` ADD DATAFILE 'ts3.ibd' FILE_BLOCK_SIZE = 8192 Engine=InnoDB;
  
  mysql> CREATE TABLE t3 (c1 INT PRIMARY KEY) TABLESPACE ts3 ROW_FORMAT=COMPACT;
  ERROR 1478 (HY000): InnoDB: Tablespace `ts3` uses block size 8192 and cannot
  contain a table with physical page size 16384

innodb_strict_mode is not applicable to general tablespaces. Tablespace management rules for general tablespaces are strictly enforced independently of innodb_strict_mode. For more information, see Section 15.1.21, “CREATE TABLESPACE Statement”.

For more information about using compressed tables with general tablespaces, see Section 17.6.3.3, “General Tablespaces”.