Ruby: SQLite3::BusyException: database is locked:

Ran into this error message whilst developing tonight: SQLite3::BusyException: database is locked:

I have two models:

• Podcasts have many Tracks
• Tracks belong to Podcasts.
• Podcast files are hosted on mixcloud.

To create a Podcast:

• user submits a url for a podcast on mixcloud
• rails app grabs json feed associated with url
• json is used to set attributes (title, image etc) on the new Podcast object

I'm trying to get my rails app to take advantage of the fact that the json feed also details the names (and artists) of the Tracks that belong to this Podcast.

I thought the following before_validation method would automatically create all associated Tracks whenever we create a new Podcast.

class Podcast < ActiveRecord::Base
  attr_accessible :mixcloud_url, :lots, :of, :other, :attrs
  has_many :tracks    
  before_validation :create_tracks
  def create_tracks
    json = Hashie::Mash.new HTTParty.get(self.json_url)    
    json.sections.each do |section|
      if section.section_type=="track"
          Track.create(:name=>section.track.name, :podcast_id=>self.id)
      end
    end             
  end
end

How can I get round this? It looks like rails (or sqlite3) doesn't like me creating new instances of an associated model in this way. How else can I do this? I suspect this is as much a rails problem as an sqlite3 one. I can post more code if it's gonna help.

Solution 1:

For anyone else encountering this issue with SQLite locking in development when a Rails console is open, try this:

Just run the following:

ActiveRecord::Base.connection.execute("BEGIN TRANSACTION; END;")

For me anyway, it appears to clear any transaction that the console was holding onto and frees up the database.

This is especially a problem for me when running delayed_job, which seems to fail at closing the transaction quite often.

Solution 2:

SQLite is not really supposed to be used for concurrent access which is the issue you are running into here. You can try increasing the timeout in your database.yml file which may be a workaround for you in this case. However, I would recommend you switch to another database that supports multiple connections like MySQL or PgSQL.

Solution 3:

For me...the issue I had was that it seemed that the Rails Console I had open for a while was locking up a connection with SQLite.

So once I exited that console, and restarted my webserver (Thin) it worked perfectly.

I tried @trisweb's suggestion but it didn't work for me.