Using Elasticsearch field collapsing to group related search results

Realestate “Developer Projects” are an important feature offered by REA to our customers (i.e. realestate agencies and property developers). An agency is able to use projects to group related listings so that they are displayed together as a group in our search results.  To implement this feature, we have chosen to use Elasticsearch’s support for  “field collapsing”.

The remainder of this article includes a summary of the problem, the approaches considered, and a bit more detail on the chosen approach.
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React Training is Coming to Melbourne

We have been busily re-building our core property listings experience using ReactJS for a while now. After the release of our revamped sold property section, we decided to find a way to engage the other areas of the company and give back to the local tech community.

With that in mind, REA Group is very excited to announce that on the 8th – 10th February 2017 we will be hosting a ReactJS workshop run by the amazing React Training team. React Training is a US based group comprised of ReactJS experts and the creators of some of the most popular open source libraries in the space, many of which we use here.

REA and React Training

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Functions as Child Components and Higher Order Components

I have recently been on a Higher Order Component (HOC) craze. HOCs are a good tool for implementing cross-cutting concerns or common functionalities, such as logging and tracking. For more information on HOCs, check out this recent post by my colleague Mehdi Mollaverdi!

Then I discovered Functions as Child Components (FaCC) and a couple of my brain cells perished. FaCC’s are components that receive a function as their child. For example:

So let’s take a trip through struggle town.

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Singletons Suck (aka Flux to Redux)

As previously mentioned (see ReactJS – Real World Examples of Higher-Order Components), we are currently re-building the core realestate.com.au property experience with ReactJS. While ReactJS may be the shiniest of a long line of JavaScript frameworks (see Derek Zoolander meme), we have been careful about pulling in new “hot right now” libraries until we felt the pain and really needed them. Cue Flux.

Flux-Capacitor

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Hunting Down Memory Issues in Rails

On a Friday a few weeks ago, we deployed a set of minor changes to one of our Rails apps. That evening, our servers started alerting on memory usage (> 95%). Our initial attempts to remedy this situation by reducing the Puma worker count on each EC2 instance didn’t help, and the memory usage remained uncomfortably high through the weekend. On Monday, we popped open NewRelic and had a look in the Ruby VM section. Indeed, both the Ruby heap and memory usage of each web worker process had begun a fairly sharp climb when we deployed on Friday, after being totally flat previously:

Heap Size Growing

However, over the same period of time, the number of objects allocated in each request remained fairly static:

Object Allocations Over the Same Period

If our requests aren’t creating more objects, but there are more and more objects in memory over time, some of them must be escaping garbage collection somehow. Continue reading