The INFORMATION_SCHEMA TABLES Table 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. 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. The row-storage format ( Fixed ,  Dynamic ,  Compressed ,  Redundant ,  Compact ). For  MyISAM  tables, Dynamic  corresponds to what  myisamchk -dvv  reports as  Packed . 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.) The average row 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. 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. 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. 4827 • INDEX_LENGTH • MAX_DATA_LENGTH • DATA_LENGTH • AVG_ROW_LENGTH • TABLE_ROWS • ROW_FORMAT • VERSION