• bugfixes
• initial support for dla Solr 4.0
• support for ruby 1.9

Source code is available on our  GitHub.

To refresh Your memory: it is a tool to visualize Solr search results and get the following information:

• why a document was placed in the results list,
• why a document wasn’t placed in the results list.

We decided to release the code, even though there are many things left that we would like to change and make better. On the other hand, there will always be places to make code better

As for the application – it was developed with the use of Ruby On Rails and even though You may see that the code was developed by people using other programming languages, we hope that You will find the application useful.

Source code is available under Apache license (2.0), but it would be very happy to hear from You if You plan to use it. We also encourage to send us corrections and report issues.

You can find the source code on Github: https://github.com/solrpl/explain

Design

Currently explain.solr.pl can analyze the query of 3.x version of Solr and it’s getting ready to be able to handle 4.0 version of Solr.

Explain visualization

In the current version explain.solr.pl visualizes score values of the given documents.

In order to add a new explain visualization you need to run your query with an additional debugQuery=on parameter and next paste the result returned by Solr to explain.solr.pl (if you will use web browser to get the results please remember to paste the page source). After hitting the “Create explain” button your explain visualization will be created and you will be taken to that visualization web page. Currently explain.solr.pl supports only results in XML format, so if you use another format (like json) please ommit the wt parameter or set it to wt=xml.

It is also possible to verify hits for any document, even one that was not found in the search results (given to Solr with the use of explainOther parameter). It can be useful to check why the given document wasn’t included in the result list.

Available information

After creating the new explain visualization you have a series of information available. Information about the query is shown ones for the whole explain, while the rest of the information is shown for each document.

Information about query

In this part of explain.solr.pl you can see:

1. Unique identifier of your explain visualization.
2. Information about debugOther parameter not being used.
   
3. The actual query.
4. Information about explain visualization being available to public.

Fields and values

In this part of the explain.solr.pl you can see information about fields and theirs values that were available in the search results.

Visualization of elements influencing total score value

The following information is visible in this part of the explain.solr.pl:

1. Percentage influence of each value on the global score value of the document.
2. Pie chart visualizing the data visible in the left column.

Getting back to once visualized explain

If you wish to get back to your once visualised explain please to the following URL address: http://explain.solr.pl/explains/EXPLAIN_ID, where EXPLAIN_ID is the unique identifier of your explain. If you don’t remember unique identifier of your visualized explain, you can find it out in the “history” page.

Hiding your explain

If you don’t want your explain information to be available to public, please uncheck the “I want this explain to be visible on history page” checkbox during explain creation. Please remember that in order to get back to private explain you will need to remember its unique identifier.

Issues raising

To raise a new issue You found in explain.solr.pl, please create a new issue on https://github.com/solrpl/explain or send a mail to explain(at)solr(dot)pl.

Request

We also have a request to the community. If you have some notes, if you encounter an error or would like some additional functionality please write an mail to explain(at)solr(dot)pl. This will allow us to better understand Your needs and will make explain.solr.pl better suite Your needs.

Something at the end

At the very end we would like to show you how the process of developing http://explain.solr.pl looks like. We used a tool called gsource

• rebuilding Lucene explain information analyzer so it is ready for the changes in Lucene 4.0 (per field similarity and flexible similarity)
• user interface rebuild along with some changes to the usability
• code cleaning and preparation for publishing sources

Fortunately autumn and winter evenings are just perfect for work We will try to make http://explain.solr.pl available as soon as possible.

Lucene Eurocon 2011

The first subject is the preparation for the upcoming Lucene Eurocon 2011 conference in Barcelona, ​​where we will have the pleasure to give a talk during the second day. For more details click here. The full plan for the upcoming conference can be found here. Come and join us!

Explain.solr.pl

The second theme, associated with the first, is a new feature on solr.pl. Often when working with Solr we need to determine why the document occurred or not in the results list, why such a score value of a given document and what affects given score value. Solr provides some tools here, but this information is not too clear and with a little more complex queries can result in a headache The functionality we are talking about is intended to present this information in a more readable form, and we hope that will help you to work with Solr More information will be shown during the presentation on the second day of Lucene Eurocon 2011 and after the premiere explain.solr.pl.