Does import sql dump wipe out current data? I have a mysql dump from version 5.5.50. I want to import it into a mysql instance on another machine, running version 5.7.13. I am using the following command to do the import:

mysql -u root -p dbname &lt; /home/dump.sql


I want to be sure that this command will completely overwrite everything on the new mysql instance. That instance already has a database with the same name and some temp data in it.

Or should I manually drop the database on the new instance prior to doing the import to ensure they're completely identical after the import?

Thanks
it is totally dependent on your mysqldump process and which options you have used while dumping. There are options like --add-drop-database,--add-drop-table  etc with mysqldump which results to wipe out your existing database with same name.
see mysql docs for futher details.