Posted by Alexey Kovyrin

Really often in customers’ application we can see a huge tables with varchar/char fields, with small sets of possible values. These are “state”, “gender”, “status”, “weapon_type”, etc, etc. Frequently we suggest to change such fields to use ENUM column type, but is it really necessary (from performance standpoint)? In this post I’d like to present a small benchmark which shows MySQL performance when you use 3 different approaches: ENUM, VARCHAR and tinyint (+joined table) columns.

In practice you can also often use 4th variant which is not comparable directly, which is using integer value and having value mapping done on application level.
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