MYSQL UPDATE Statement and Already Updated Records

In considering how to update a table based on a set of input data that might or might not actually change the records, I was wondering how MySQL processed an UPDATE where the record in question was already up to date. The question would be overhead in processing.

If the record is left alone, there would be less processing. There is still some overhead, but if you have a number of potential updates, and cannot be certain whether the submitted data differs from the existing data, there is no way to avoid some overhead.

This isn’t the sort of thing that is generally discussed on web sites, though you can often find overhead information in comments on some of the technical sites.

In any case, in the MySQL manual reference on UPDATE I found this:

If you set a column to the value it currently has, MySQL notices this and does not update it.

Without further testing, I’ll consider this an answer, and run my bulk update.