What is the correct way to build a new index on a large table?

Question

MySQL

There is a big table, more than 15 million records. Building a new composite index from 3 fields took more than an hour in the "copy to tmp table" stage, after which I got tired of waiting, I realized that it was a bad job and canceled the process)
Are there any recommendations to speed up this process? change some server settings or something like that?

Answer 1

The question has already been repeatedly raised
The general principle of updating the structure of large or loaded tables.
It concerns both indexes and adding/removing columns
https://toster.ru/answer?answer_id=1023774#answers...
Clarification.
For indexes, it will be faster to turn them off first, insert all the data. And only then create indexes

Answer 2

It won't be faster, but without a global lock on the base.
For example, I added an index to a table of ~ 30Gb or 40 million records, it took about an hour