what do you mean "ROW_FORMAT in NULL" and "ROW_FORMAT is every NULL" ?

serg

I changed the text to make it more clearly.

MDEV-22343 did not change anything in this regard. The introduction of MDEV-12026 innodb_checksum_algorithm=full_crc32 did.

The original motivation for encoding ROW_FORMAT in the tablespace flags was to avoid trouble when downgrading from the InnoDB Plugin for MySQL 5.1 to the built-in MySQL 5.1 that would not recognize ROW_FORMAT=DYNAMIC or ROW_FORMAT=COMPRESSED.

At least starting with MariaDB Server 10.3, we have a better way of detecting the compatibility of a table: opening and examining the clustered index root page (page 3 in the .ibd file). MariaDB Server 10.3 would nicely refuse to open a table where MDEV-15562 had been used (and the MDEV-20590 compatibility constraint innodb_instant_alter_column_allowed=add_last was not set).

I tried the following in MariaDB Server 10.4:

--source include/have_innodb.inc

select * from information_schema.innodb_sys_tablespaces;

The ROW_FORMAT of the system tables (in the mysql schema) will be reported as either Dynamic or NULL depending on how I invoke the test:

./mtr --mysqld=--innodb-sys-tablespaces MDEV-32230

./mtr --mysqld=--innodb-sys-tablespaces --mysqld=--innodb-checksum-algorithm=full_crc32 MDEV-32230

MDEV-19534 made innodb_checksum_algorithm=full_crc32 the default in MariaDB Server 10.5. In the MariaDB Enterprise Server, it is the default already starting with 10.4.

ROW_FORMAT is not always NULL in 10.6:

On 10.6.15:

SELECT * FROM INFORMATION_SCHEMA.INNODB_SYS_TABLES;

+----------+----------------------------+------+--------+-------+------------+---------------+------------+

| TABLE_ID | NAME                       | FLAG | N_COLS | SPACE | ROW_FORMAT | ZIP_PAGE_SIZE | SPACE_TYPE |

+----------+----------------------------+------+--------+-------+------------+---------------+------------+

|       18 | test/t1                    |   33 |      4 |     5 | Dynamic    |             0 | Single     |

|       20 | test/t2                    |    1 |      5 |     7 | Compact    |             0 | Single     |

|       21 | test/t3                    |    0 |      5 |     8 | Redundant  |             0 | Single     |

|       22 | test/t4                    |   41 |      5 |     9 | Compressed |          8192 | Single     |

+----------+----------------------------+------+--------+-------+------------+---------------+------------+

The documentation on https://mariadb.com/kb/en/information-schema-innodb_sys_tables-table/ appears to be correct, so I'm unclear what needs to be updated.

The innodb_checksum_algorithm=full_crc32 is not available for ROW_FORMAT=COMPRESSED tables. At the time we implemented the full_crc32 format, I did not want to introduce a new ROW_FORMAT=COMPRESSED file format.

Those tables originally used the zlib Adler32, which was working fine. I just realized that the current default (which is the only option after MDEV-25105) made things less secure, by making the checksum a XOR of 3 CRC-32 checksum. A single checksum over the entire page would be faster and better.

greenman, this bug is about INFORMATION_SCHEMA.INNODB_SYS_TABLESPACES and not INFORMATION_SCHEMA.INNODB_SYS_TABLES. The last 3 columns are kind of "virtual", probably derived from FLAG, except SPACE_TYPE, which is derived from SPACE.