deltoid_delta

Delta indexing plugin for Thinking Sphinx that sets a reindex flag in memcached whenever a model needs to be reindexed. It is expected to be used along with the Deltoid daemon, which polls memcached and rebuilds indices whenever the reindex flags are set.

Installation

Installation is as simple as adding the deltoid_delta gem to your Gemfile:

gem 'deltoid_delta', :git => "git://github.com/satisfaction/deltoid_delta.git"

You may want to tag it to a specific release:

gem 'deltoid_delta', :git => "git://github.com/satisfaction/deltoid_delta.git", :tag => "0.0.14"

Then bundle your gems:

bundle install

You'll then need to require deltoid_delta in your Rails project. I've typically put this in an initializer along with all my other Sphinx-related configuration.

require 'deltoid_delta'

Using deltoid_delta in your models

Thinking Sphinx allows you to specify which delta indexing strategy to use by setting the :delta property to the name or instance of a class. Within your define_index block, set the property like so:

set_property  :delta => "DeltoidDelta"

deltoid_delta is based on the datetime delta strategy, and supports all of the same options, such as :threshold and :delta_column. The defaults for :threshold and :delta_column are also the same (1 day and updated_at, respectively).

The Deltoid Daemon process

All of the actual delta indexing work is performed within the deltoid daemon process, included in the gem. This daemon will check a memcached server every second to see if a dirty flag has been set for an index. This dirty flag is automatically set anytime one of your indexed models is updated.

Whenever the deltoid daemon notices your indexes are dirty, it will rebuild the delta indexes for you. It will first clear the dirty flag, and then invoke the Sphinx indexer process to rebuild the affected indexes.

The deltoid daemon also performs a complete reindex of the indexes once a day at midnight. Having all your indexing in one process avoids multiple indexer processes from corrupting your indexes.

Rake Tasks

To properly manage your indexes, the deltoid daemon needs your Sphinx configuration file, as well as your memcached.yml file. The deltoid_delta gem comes with rake tasks that you can use to manage the daemon process.

To use the rake tasks, you should include them in your Rakefile:

require 'deltoid_delta/tasks'

This will give you the following rake tasks for managing the deltoid daemon included in the gem:

rake deltoid:env      # Displays the calculated deltoid daemon configuration values
rake deltoid:restart  # Restarts the deltoid daemon process
rake deltoid:run      # Runs the deltoid daemon process in the foreground
rake deltoid:start    # Starts the deltoid daemon process
rake deltoid:stop     # Stops the deltoid daemon process

The deltoid:env task is really useful for debugging what the tasks will run, or as a starting point for writing your own management scripts.

Copyright

Copyright (c) 2010 Get Satisfaction. See LICENSE.txt for further details.