What is the 'repair code' in MySQL?

Question

OK I was adding an index to a table, and I checked on progress using show processlist and under state it output Repair by sorting.

From the MySQL docs:

Repair by sorting

The repair code is using a sort to create indexes.

So what is the 'repair code'? Did something break?

Answer 1

Nothing broke, it's just part of the process of rebuilding indexes on a table. This can take quite a while on very large tables.