Question

I’m having trouble using delayed deltas with thinking_sphinx. This is the model:

Event
  has_many :subscriptions
  has_many :users, :through => :subscriptions
  ...
  define_index do
    indexes name
    indexes users(:id), :as => :user_id
    set_property :delta => :delayed
  ...

Subscription
  belongs_to :event
  belongs_to :user

User
  has_many :subscriptions
  has_many :events, :through => :subscriptions

When a user adds/removes a subscription I set the delta flag to all the corresponding events through the subscription model callbacks like this:

after_save :set_events_delta_flag
after_destroy :set_events_delta_flag

def set_events_delta_flag
  Event.define_indexes
  sql = "UPDATE events SET delta = true FROM subscriptions"
  sql << " WHERE events.id = subscriptions.event_id AND (subscriptions.id = #{self.id})"
  Event.connection.update(sql)
  Event.index_delta
end

It works ok when a user adds a subscription: the callback runs and then a ThinkingSphinx::Deltas::DeltaJob job runs and updates the index. However when a user removes a subscription the callback and the DeltaJob run, but it seems that the index does not get updated:

If I do something like:

Event.search("". :with => {:user_id => XX}).search_count

before and after remove a subscription, the count does not change (it changes before and after adding a subscription)

is this an expected behavior? What am I doing wrong?

Update: It seems that Sphinx storig two copies of the same document (one in the core index and one in the delta index) is the cause of the problem.

Answer 1

With upgrade to Sphinx 2.0.3, this problem of having 2 indices will go away. the indices will be merged into single. You can try upgrading it.