rails/rails — Issue #3813: Horrible performance with ActiveRecord 3.1
Author: pimeys
Created: 2011-11-30 17:10:14+00:00
State: open

If using MySQL tables with no primary keys, ActiveRecord's performance will drop significantly. Operations like `create` will generate lots of queries like the following:

```sql
SHOW INDEX FROM `table_name` WHERE Key_name = 'PRIMARY'
```

I've included a small fix to get rid of the problem.