Is "--one-database" safe to use for importing from a dump?
The only risk is time and missing out on trigger stored procedures.

Normally, mysqldumps are done in alphabetical order.

When loading a dump, expect databases aardvark, alligator and antelope to load early. Any database like zoo and zebra would require time because --one-database does not force a mysqldump to load the specified database. The entire dump must be read until the specified database is in use.

For example, mysql --one-database zebra will read the entire mysqldump but start loading when it gets to the line the dump that says

USE zebra


Then, all INSERT INTO commands are processed until the EOF or until it see another line like

USE zimbabwe


Some developers I know would wait until the database they chose is loaded. Then, hit Ctrl-C. I would not risk that. You should make sure that all triggers and stored procedures are loaded as well.

If you cannot wait and want to Ctrl-C, login to mysql while the dump is still loading and make sure all tables, views, triggers, and stored procedures have been loaded.