PAGE_CHECKSUM

The PAGE_CHECKSUM table option specifies whether a page checksum for the table should be enabled. The checksum can either be switched on (value 1) or off (value 0). The default value of this option is implied by the maria_page_checksum variable.

Because the default value of the PAGE_CHECKSUM option is configurable, the checksum setting is always included in the output of SHOW CREATE TABLE if it was enabled when the table was created.

TRANSACTIONAL

Maria tables can be either transactional or non-transactional. For Maria versions less than 2.0, TRANSACTIONAL means crash-safe. Full transaction support will only be available with Maria 2.0 and later.

Changes to transactional tables are recorded in the Maria log and use slightly more space per row than non-transactional tables. By default all tables are transactional; that is, TRANSACTIONAL=1 is implied within the CREATE TABLE definition. This means that the transactional status of the table is not written in the output of the SHOW CREATE TABLE output:

mysql> create table maria_trans (id int, title char(20)) engine=Maria;
Query OK, 0 rows affected (0.05 sec)

mysql> SHOW CREATE TABLE maria_trans;
+-------------+---------------------------------------+
| Table       | Create Table                          |
+-------------+---------------------------------------+
| maria_trans | CREATE TABLE `maria_trans` (
   `id` int(11) DEFAULT NULL,
   `title` char(20) DEFAULT NULL
) ENGINE=MARIA DEFAULT CHARSET=latin1 PAGE_CHECKSUM=1 |
+-------------+---------------------------------------+
1 row in set (0.00 sec)
      

If you create a non-crash safe (non-transactional) table then the option is shown

mysql> CREATE TABLE maria_nontrans (id INT, title CHAR(20)) ENGINE=Maria TRANSACTIONAL=0;
Query OK, 0 rows affected (0.02 sec)

mysql> SHOW CREATE TABLE maria_nontrans;
+----------------+----------------------------------------------------+
| Table          | Create Table                                       |
+----------------+----------------------------------------------------+
| maria_nontrans | CREATE TABLE `maria_nontrans` (
   `id` int(11) DEFAULT NULL,
   `title` char(20) DEFAULT NULL
) ENGINE=MARIA DEFAULT CHARSET=latin1 PAGE_CHECKSUM=1 TRANSACTIONAL=0 |
+----------------+----------------------------------------------------+
1 row in set (0.00 sec)

Currently, transactional tables cannot handle SPATIAL or FULLTEXT indexes. You must use a non-transactional table if you want to use these index key types. If you try to create a table with these options, then an error will occur during CREATE TABLE.

TABLE_CHECKSUM, CHECKSUM

Forces MySQL to maintain a live checksum for all rows in the table. This maintains a rolling checksum (that is, one that changes when the table data changes), and can be used to identify corrupted tables. This is identical to the CHECKSUM on MyISAM tables.

The CHECKSUM TABLE statement, which returns the checksum for a given table, ignores record's columns which have a NULL value. This is different behavior from standard MySQL 5.1.

FIXED — identical to the FIXED row format used by MyISAM. Must be used with non-transactional tables (that is, where TRANSACTIONAL=0).

DYNAMIC — identical to the DYNAMIC row format used by MyISAM. Must be used with non-transactional tables (that is, where TRANSACTIONAL=0).

PAGE — new Maria row format where data and index information is written into pages. The PAGE option can be used with TRANSACTIONAL=0 or TRANSACTIONAL=1. The PAGE format uses a different caching mechanism than MyISAM. For more information, see Section 13.5.1, “Maria Configuration”.

Maria data pages in PAGE format have an overhead of 10 bytes/page and 5 bytes/row. Transaction and multiple concurrent writer support will use an additional overhead of 7 bytes for new rows, 14 bytes for deleted rows and 0 bytes for old compacted rows.