#306 ElasticSearch Part 1

@Thomas: I've used Sphinx, Solr and ElasticSearch in production and my favorite is ElasticSearch for a few reasons:

1. Sphinx and Solr both index documents periodically (with a large delay or manual re-index by default) so it's more difficult to index documents near real time. ElasticSearch has a default delay of one second.
2. ElasticSearch has built-in cluster support for High Availability solutions. This is possible in Sphinx/Solr as well but again more difficult to set up.
3. ElasticSearch and Solr both have built in "More Like This" queries, which is the main reason I had to stop using Sphinx. Sphinx doesn't have a built in solution for providing "similar" documents.
4. ElasticSearch is the easiest to set up and get running for development AND production. Sphinx comes close because you only have to edit one configuration file. Solr is the hardest because you need to optimize it for production (and not use the built in Solr package provided with Sunspot, for example). There are lots of configuration files with Solr and usually you would want to use Tomcat to serve the search engine in production, which requires a lot of configuration by itself. It's also extremely simple to set up multiple indexes (or version your indexes) in ElasticSearch.
5. The ElasticSearch API is JSON-based, so you can integrate the search engine easily with any application. You don't NEED a wrapper library to get up and running fast.

After working with different search engines for a while now, most of them require lots of time tweaking and configuring to fit your needs. The biggest advantage for ElasticSearch is the built-in functionality that usually requires lots of configuration. Less configuring means fewer opportunities to break and more time to spend concentrating on more important things like building your website! Also check out ElasticSearch's percolate queries...another cool feature that you may find useful.

@Jarron,

In sphinx, delta indexing acts like a secondary index where you can index a smaller number of documents (such as new documents added today) and your site will search the main + delta index. You need to merge the delta index with the main index frequently (once a day or once a week at least) by using a cron job or other periodically running task. Also, the delta index doesn't imply real-time indexing either, you still have to periodically update the delta index as well. It's not real time. Last time I used sphinx about a year ago, they were experimenting with an update API where you can just update the document in the index, which would be real time.

Technically, it should be possibly, when you'd use the :load option. Using filters and not using :load is of course much more preferable.

I'm answering to my own question: just use the total attribute on the search result:

@articles = Article.search(params)
@total_articles = @articles.total

Thanks again for the great screencasts !

I am going to respond to your comment assuming that you are a true beginner. If I am saying something you already know or find the tone of my response offensive then I am sorry, I am only trying to help.

Before I continue to answer your comment I ask you to please not type messages in all-capitals, it appears as if you are shouting and comes across quite rude. Also saying things like "you must help me or I will go insane" doesn't inspire others to help you out, its more likely that you'll get ignored. No matter how desperate you are, if you want someone's help the best thing to do is to be polite and clearly explain your problem and adding as much relevant information as possible. You will find that this applies to communications on most tech resources (mailing lists, forums, etc.)

Now on to your problems:

I'm afraid you made a beginner's mistake, running rake db:setup will setup a fresh database, so that's what happened (that's a standard rake task in Rails). If you ran that command on your production environment the only thing you can do is restore your latest database backup. If you don't have a backup there's really nothing that can be done.

As for the template missing error, its hard to say without knowing your codebase. If you've been editing code on your production system (which you really shouldn't be doing, development should be done on in its own place, for example on your own machine) you will have to debug the error and fix it.

I hope that my reply gives you some insight into your problems.

I had a similar issue. I got it all stood up but had an index error.

I had to do something like:

rake environment tire:import CLASS='Article'

to re-index (or just index for the first time) everything in the db.

and if i did? can I rollback somehow???

Agree! It would be awesome! Been trying to setup Elasticsearch with the new Elasticsearch rails gem, but not finding enough/clear documentation on how to migrate from Tire. Railscasts are awesome!

I also agree!

agreed

Agree