mysql 8.0 表的 ROW_FORMAT [=] {DEFAULT|DYNAMIC|FIXED|COMPRESSED|REDUNDANT|COMPACT}

os: centos 7.4
db: mysql 8.0

version

# cat /etc/centos-release
CentOS Linux release 7.4.1708 (Core) 

# mysql

root@localhost 08:03:03 [test]> select version();
+-----------+
| version() |
+-----------+
| 8.0.20    |
+-----------+
1 row in set (0.00 sec)

row_format

root@localhost 07:55:38 [test]> show table status like 'tmp_t100'\G
*************************** 1. row ***************************
           Name: tmp_t100
         Engine: InnoDB
        Version: 10
     Row_format: Dynamic
           Rows: 994137
 Avg_row_length: 100
    Data_length: 100286464
Max_data_length: 0
   Index_length: 54165504
      Data_free: 4194304
 Auto_increment: NULL
    Create_time: 2020-09-10 07:45:39
    Update_time: 2020-09-10 07:27:07
     Check_time: NULL
      Collation: utf8mb4_0900_ai_ci
       Checksum: NULL
 Create_options: 
        Comment: 
1 row in set (0.00 sec)

root@localhost 08:01:24 [test]> select * from information_schema.innodb_tables where name='test/tmp_t100'\G
*************************** 1. row ***************************
     TABLE_ID: 1083
         NAME: test/tmp_t100
         FLAG: 33
       N_COLS: 6
        SPACE: 26
   ROW_FORMAT: Dynamic
ZIP_PAGE_SIZE: 0
   SPACE_TYPE: Single
 INSTANT_COLS: 0
1 row in set (0.00 sec)

ROW_FORMAT [=] DEFAULT

The default row format is defined by innodb_default_row_format, which has a default setting of DYNAMIC. The default row format is used when the ROW_FORMAT option is not defined or when ROW_FORMAT=DEFAULT is used.

If the ROW_FORMAT option is not defined, or if ROW_FORMAT=DEFAULT is used, operations that rebuild a table also silently change the row format of the table to the default defined by innodb_default_row_format.

root@localhost 00:48:07 [test]> show global variables like '%innodb_default_row_format%';
+---------------------------+---------+
| Variable_name             | Value   |
+---------------------------+---------+
| innodb_default_row_format | dynamic |
+---------------------------+---------+
1 row in set (0.01 sec)

ROW_FORMAT [=] DYNAMIC

ROW_FORMAT [=] FIXED

ROW_FORMAT=FIXED is not supported.
If ROW_FORMAT=FIXED is specified while innodb_strict_mode is disabled, InnoDB issues a warning and assumes ROW_FORMAT=DYNAMIC.
If ROW_FORMAT=FIXED is specified while innodb_strict_mode is enabled, which is the default, InnoDB returns an error.

ROW_FORMAT [=] COMPRESSED

The COMPRESSED row format is a variation of the COMPACT row format.

ROW_FORMAT [=] REDUNDANT

The REDUNDANT format provides compatibility with older versions of MySQL.

ROW_FORMAT [=] COMPACT

The COMPACT row format reduces row storage space by about 20% compared to the REDUNDANT row format, at the cost of increasing CPU use for some operations. If your workload is a typical one that is limited by cache hit rates and disk speed, COMPACT format is likely to be faster. If the workload is limited by CPU speed, compact format might be slower.

参考:
https://dev.mysql.com/doc/refman/8.0/en/create-table.html

https://dev.mysql.com/doc/refman/8.0/en/innodb-row-format.html#innodb-row-format-defining
https://dev.mysql.com/doc/refman/8.0/en/innodb-row-format.html#innodb-row-format-dynamic
https://dev.mysql.com/doc/refman/8.0/en/innodb-row-format.html#innodb-row-format-compressed
https://dev.mysql.com/doc/refman/8.0/en/innodb-row-format.html#innodb-row-format-redundant
https://dev.mysql.com/doc/refman/8.0/en/innodb-row-format.html#innodb-row-format-compact