Datetime Deltas for Thinking Sphinx


You’ll need Thinking Sphinx 1.3.0 or later (v3 is now supported since the 2.0.0 release of this gem).

gem install ts-datetime-delta

In your Gemfile, you can use it like so:

gem 'ts-datetime-delta', '~> 2.0.1',
  :require => 'thinking_sphinx/deltas/datetime_delta'

Or if you’re still on Rails 2, then put this in your environment.rb file with the rest of your gem dependencies:

config.gem 'ts-datetime-delta',
  :lib     => 'thinking_sphinx/deltas/datetime_delta'
  :version => '>= 2.0.1'

No matter which version of Rails, you’ll need to add the following line to the bottom of your Rakefile:

require 'thinking_sphinx/deltas/datetime_delta/tasks'


For the indexes you want to use this delta approach, make sure you set that up in your index definition. For Thinking Sphinx v3, that’ll look like this:

  :with  => :active_record,
  :delta => ThinkingSphinx::Deltas::DatetimeDelta
) do
  # ...

But for Thinking Sphinx v1/v2, it belongs within your define_index blocks:

define_index do
  # ...

  set_property :delta => :datetime

If you want to use a column other than updated_at, you can specify it using the :column option. The same goes for the threshold, which defaults to one day.

Again, Thinking Sphinx v3 expects these options outside the block:

  :with          => :active_record,
  :delta         => ThinkingSphinx::Deltas::DatetimeDelta,
  :delta_options => {:threshold => 1.hour, :column => :changed_at}
) do
  # ...

But Thinking Sphinx v1/v2 it goes within the define_index block:

set_property :delta => :datetime,
  :threshold    => 1.hour,
  :column => :changed_at

Then, while your Rails application is running, you’ll need to run the delta indexing rake task regularly – as often as your threshold, allowing for some time for the indexing to actually happen.

For example, if you’re going to run the delta indexing task every hour, I would recommend setting your threshold to 70 minutes.

To ensure this rake task is called regularly, it’s best to set it up as a recurring task via cron or similar tools.

rake thinking_sphinx:index:delta

The shorthand version is:

rake ts:in:delta



Copyright © 2009-2014 Pat Allan, and released under an MIT Licence.