Julian Doherty

Using Stats To Not Break Search

How do you change around pretty much everything in your search backend, but still remain confident that nothing has broken? (at least not in a way you didn’t expect).

We can use statistics to do that. In particular, a technique called Spearman’s rank correlation coefficient. Let’s have a look at it, and see how we can use it to compare search results before and after a change to make sure relevancy rankings haven’t gotten screwed up in the process.


Moving the Marketplaces to Elasticsearch

TL;DR: How we got from the top chart to the bottom chart.

Solr Response ES Response

We have been playing with adding new facets to search on the Marketplaces, but Solr was not making it easy for us due to slow indexing and annoying XML schema files. I experimented with Elasticsearch during a dev iteration and decided it was worth switching.

So we did it. And I’m going to tell you how we did it.


We are the people who build the many Envato sites and products.

We think we build great products in interesting ways, and this is our place to talk about it. At Envato, we help our community learn and earn online and in that spirit it is important for us to share what we learn.

You’ll find out more about the technical choices we make, including the ones that don’t turn out as we hope. We’ll describe our approach to solving problems rather than simply adding features. Along the way, you will meet the team members and find out what makes them tick.

Welcome to webuild.envato.com.

The Team