h1. Datetime Deltas for Thinking Sphinx
h2. Installation
You'll need Thinking Sphinx 1.3.0 or later (v3 is now supported since the 2.0.0 release of this gem).
<pre>gem install ts-datetime-delta
</pre>
In your Gemfile, you can use it like so:
<pre><code>gem 'ts-datetime-delta', '~> 2.0.1',
:require => 'thinking_sphinx/deltas/datetime_delta'</code></pre>
Or if you're still on Rails 2, then put this in your @environment.rb@ file with the rest of your gem dependencies:
<pre><code>config.gem 'ts-datetime-delta',
:lib => 'thinking_sphinx/deltas/datetime_delta' :version => '>= 2.0.1'</code></pre>
No matter which version of Rails, you'll need to add the following line to the bottom of your @Rakefile@:
<pre>require 'thinking_sphinx/deltas/datetime_delta/tasks'
</pre>
h2. Usage
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:
<pre><code>ThinkingSphinx::Index.define(:book,
:with => :active_record, :delta => ThinkingSphinx::Deltas::DatetimeDelta
) do
# ...
end</code></pre>
But for Thinking Sphinx v1/v2, it belongs within your @define_index@ blocks:
<pre><code>define_index do
# ... set_property :delta => :datetime
end</code></pre>
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:
<pre><code>ThinkingSphinx::Index.define(:book,
:with => :active_record, :delta => ThinkingSphinx::Deltas::DatetimeDelta, :delta_options => {:threshold => 1.hour, :column => :changed_at}
) do
# ...
end</code></pre>
But Thinking Sphinx v1/v2 it goes within the @define_index@ block:
<pre><code>set_property :delta => :datetime,
:threshold => 1.hour, :column => :changed_at</code></pre>
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.
<pre>rake thinking_sphinx:index:delta
</pre>
The shorthand version is:
<pre>rake ts:in:delta
</pre>
h2. Contributors
-
“W. Andrew Loe III”:andrewloe.com/ - Environment variable for disabling merging.
-
“Kirill Maximov”:kirblog.idetalk.com - Handling nil timestamp column values for toggled checks.
-
“Timo Virkkala”:github.com/weetu - Thinking Sphinx v3 compatibility,fix for null timestamps.
-
“Cedric Maion”:github.com/cmaion - Fix for keeping custom options persisted.
h2. Copyright
Copyright © 2009-2014 Pat Allan, and released under an MIT Licence.