mysqlimport locks all tables system wide

I recently developed a script that spawns multiple processes to import tables in parallel using mysqlimport and a –tab type mysqldump export. On the development server it works very well and compared to a standard mysql db_name < backup.sql type of import it cuts the time from around 15 minutes to 4 or 5 minutes.

The problem is on our production server this script seems to be locking tables system wide. That is to say, I’m importing a backup to a completely different database but our live application tables still end up locked. A SHOW PROCESSLIST confirms that tables on our live db are indeed locked but no INSERT or UPDATE queries are running on any tables in that database.

Why is this happening? Is there a configuration variable / setting that I can adjust to prevent this lock from happening?