percona_server_views
SYNOPSIS
Percona server views: views enhancing INFORMATION_SCHEMA tables available in Percona Server.
- innodb_index_rows: number of row cardinality per keys per columns in InnoDB tables
- innodb_index_stats: estimated InnoDB depth & split factor of key's B+ Tree
DESCRIPTION
These views rely on the INNODB_INDEX_STATS feature to be enabled. The views are compatible with recent versions of Percona Server (due to changes to INNODB_INDEX_STATS schema in Percona Server 5.5.8, these views are incompatible with earlier versions).
EXAMPLES
Examine keys selectivity/cardinality on a specific table:
mysql> SELECT * FROM common_schema.innodb_index_rows WHERE TABLE_SCHEMA='sakila' AND TABLE_NAME='inventory'; +--------------+------------+----------------------+--------------+--------------+-------------------------+-------------------------+ | TABLE_SCHEMA | TABLE_NAME | INDEX_NAME | SEQ_IN_INDEX | COLUMN_NAME | is_last_column_in_index | incremental_row_per_key | +--------------+------------+----------------------+--------------+--------------+-------------------------+-------------------------+ | sakila | inventory | PRIMARY | 1 | inventory_id | 1 | 1 | | sakila | inventory | idx_fk_film_id | 1 | film_id | 1 | 5 | | sakila | inventory | idx_store_id_film_id | 1 | store_id | 0 | 4478 | | sakila | inventory | idx_store_id_film_id | 2 | film_id | 1 | 2 | +--------------+------------+----------------------+--------------+--------------+-------------------------+-------------------------+