MySQL index cardinality - performance vs storage efficiency
- by Sean
Say you have a MySQL 5.0 MyISAM table with 100 million rows, with one index (other than primary key) on two integer columns.
From my admittedly poor understanding of B-tree structure, I believe that a lower cardinality means the storage efficiency of the index is better, because there are less parent nodes. Whereas a higher cardinality means less…