The storage engine for the table. See Chapter 15, The InnoDB Storage Engine , and Chapter 16, Alternative Storage Engines . 

For partitioned tables, ENGINE  shows the name of the storage engine used by all partitions. 

• VERSION 

This column is unused. With the removal of .frm  files in MySQL 8.0, this column now reports a hardcoded value of 10 , which is the last .frm  file version used in MySQL 5.7. 

• ROW_FORMAT 

The row-storage format ( Fixed , Dynamic , Compressed , Redundant , Compact ). For MyISAM  tables, Dynamic  corresponds to what myisamchk -dvv  reports as Packed . 

• TABLE_ROWS 

The number of rows. Some storage engines, such as MyISAM , store the exact count. For other storage engines, such as InnoDB , this value is an approximation, and may vary from the actual value by as much as 40% to 50%. In such cases, use SELECT COUNT(*)  to obtain an accurate count. 

TABLE_ROWS  is NULL  for INFORMATION_SCHEMA  tables. 

For InnoDB  tables, the row count is only a rough estimate used in SQL optimization. (This is also true if the InnoDB  table is partitioned.) 

• AVG_ROW_LENGTH 

The average row length. 

• DATA_LENGTH 

For MyISAM , DATA_LENGTH  is the length of the data file, in bytes. 

For InnoDB , DATA_LENGTH  is the approximate amount of space allocated for the clustered index, in bytes. Specifically, it is the clustered index size, in pages, multiplied by the InnoDB  page size. 

Refer to the notes at the end of this section for information regarding other storage engines. 

• MAX_DATA_LENGTH 

For MyISAM , MAX_DATA_LENGTH  is maximum length of the data file. This is the total number of bytes of data that can be stored in the table, given the data pointer size used. 

Unused for InnoDB . 

Refer to the notes at the end of this section for information regarding other storage engines. 

• INDEX_LENGTH 

For MyISAM , INDEX_LENGTH  is the length of the index file, in bytes. 

For InnoDB , INDEX_LENGTH  is the approximate amount of space allocated for non-clustered indexes, in bytes. Specifically, it is the sum of non-clustered index sizes, in pages, multiplied by the InnoDB  page size. 

Refer to the notes at the end of this section for information regarding other storage engines. 

