SQLite3::BusyException

You mentioned that this is a Rails site. Rails allows you to set the SQLite retry timeout in your database.yml config file:

production:
  adapter: sqlite3
  database: db/mysite_prod.sqlite3
  timeout: 10000

The timeout value is specified in miliseconds. Increasing it to 10 or 15 seconds should decrease the number of BusyExceptions you see in your log.

This is just a temporary solution, though. If your site needs true concurrency then you will have to migrate to another db engine.

By default, sqlite returns immediatly with a blocked, busy error if the database is busy and locked. You can ask for it to wait and keep trying for a while before giving up. This usually fixes the problem, unless you do have 1000s of threads accessing your db, when I agree sqlite would be inappropriate.

    // set SQLite to wait and retry for up to 100ms if database locked
    sqlite3_busy_timeout( db, 100 );

All of these things are true, but it doesn't answer the question, which is likely: why does my Rails app occasionally raise a SQLite3::BusyException in production?

@Shalmanese: what is the production hosting environment like? Is it on a shared host? Is the directory that contains the sqlite database on an NFS share? (Likely, on a shared host).

This problem likely has to do with the phenomena of file locking w/ NFS shares and SQLite's lack of concurrency.