Playback: 20 Billion Documents in the Cloud with HomeAway (Expedia) - MongoDB World 2018

Dj Walker-Morgan

#MongoDB World Old

Playback is where the MongoDB blog brings you selected talks from around the world and around the industry. Here, we are showcasing the great talks at MongoDB World 2018 from people running MongoDB in production and at scale.

Behind the scenes of its holiday rental business, HomeAway analyses its interaction with users like you, linking together the many interactions you might have when booking that rental over many weeks. Pulling those many sessions, usually over multiple devices, is a real challenge.

HomeAway chose MongoDB as the engine to persist the linked data. In their MongoDB World 2018 talk, HomeAway Data Architect Singaram Rangunathan and Principal Software Engineer Naveen Malhotra, talk about why they chose MongoDB.

HomeAway's solution is based around a KeyRing which gathers identifiable user sessions together. When common keys are spotted between KeyRings, they are chained together so that a complete picture of a user's overall experience is constructed.

The process sees all the incoming session documents being processed through a Kafka pipeline which persists the links between KeyRings and KeyChains in MongoDB. Rangunathan discusses how HomeAway worked out how to get the scale they needed in the cloud to process the data. He also talks about using MongoDB sharding for horizontal scaling, pre-splitting the sharding keys for best performance and how they selected the appropriate cloud hardware to run their solution on.