EmergencyEMERGENCY? Get 24/7 Help Now!


 | March 20, 2010 |  Posted In: MySQL, Percona Software


In Released and new coming features I did not mentioned two additional INFORMATION_SCHEMA tables available in XtraDB:
It is


These table show statistics about InnoDB tables ( taken from InnoDB data dictionary).


  • | table_name | table name in InnoDB internal style (‘database/table’) |
  • | rows | estimated number of all rows |
  • | clust_size | cluster index (table/primary key) size in number of pages|
  • | other_size | other index (non primary key) size in number of pages|
  • | modified | internal counter to judge whether statistics recalculation should be done |


  • | table_name | table name in InnoDB internal style (‘database/table’) |
  • | index_name | index name |
  • | fields | How many fields the index key has. (it is internal structure of InnoDB, it may be larger than the ‘CREATE TABLE’) |
  • | row_per_keys | estimate rows per 1 key value. ([1 column value], [2 columns value], [3 columns value], …) |
  • | index_size | index size in pages |
  • | leaf_pages | number of leaf pages |

Using these stats you can estimate how big is index is, and also what is statistics per index (or at least what InnoDB thinks about statistics in index)

Vadim Tkachenko

Vadim Tkachenko co-founded Percona in 2006 and serves as its Chief Technology Officer. Vadim leads Percona Labs, which focuses on technology research and performance evaluations of Percona’s and third-party products. Percona Labs designs no-gimmick tests of hardware, filesystems, storage engines, and databases that surpass the standard performance and functionality scenario benchmarks. Vadim’s expertise in LAMP performance and multi-threaded programming help optimize MySQL and InnoDB internals to take full advantage of modern hardware. Oracle Corporation and its predecessors have incorporated Vadim’s source code patches into the mainstream MySQL and InnoDB products. He also co-authored the book High Performance MySQL: Optimization, Backups, and Replication 3rd Edition.


  • Arjen, Shlomi,

    What we show there is already available information in InnoDB data dictionary.
    What you ask needs some additional changes in InnoDB data dict, which may be not easy to
    archive (may break compatibility with current data dict), but it is hard to say, I did not look into yet.

  • Cannot find or open table mysql/innodb_index_stats from the internal data dictionary of InnoDB though the .frm file for the table exists. Maybe you have deleted and recreated InnoDB data files but have forgotten to delete the corresponding .frm files of InnoDB tables, or you have moved .frm files to another database? or, the table contains indexes that this version of the engine doesn’t support. why?

  • I have installed mysql5.6.10, following error is seen in .err
    InnoDB: Error: Table “mysql”.”innodb_table_stats” not found.

    When Mysql services is started, after deleting ib log and data files.

    Please help

Leave a Reply


Percona’s widely read Percona Data Performance blog highlights our expertise in enterprise-class software, support, consulting and managed services solutions for both MySQL® and MongoDB® across traditional and cloud-based platforms. The decades of experience represented by our consultants is found daily in numerous and relevant blog posts.

Besides specific database help, the blog also provides notices on upcoming events and webinars.
Want to get weekly updates listing the latest blog posts? Subscribe to our blog now! Submit your email address below and we’ll send you an update every Friday at 1pm ET.

No, thank you. Please do not ask me again.