Using sqlite3 on multithreaded server, is it possible?

I wrote a tiny multithreaded server which need to run queries against a local sqlite3 file.
For some reason the connection to the db file ie “open” doens’t work.
I know that sqlite3 has some locking issues but I assumed that the sqlite3 gem handles this somehow.
Is there a specific flag or way to handle sqlite3 gem in/under a multithreaded server?