multiple columns), this information becomes even more interesting, 
as it lets us examine the reduction in cardinality (and improvement of selectivity) per column. 
However, the Percona Server patch only informs us with numbers. 
</p>

<p><i>innodb_index_rows</i> extends that information and adds column information. 
It lists column names and their sequence within the key, and provides with easier to read format.</p>

<p>This view depends upon the <a href="http://www.percona.com/docs/wiki/percona-server:fea