Andy Summers, Software Engineer

@NoSQL (or Not Only SQL)

We are the UK’s #1 classifieds website

and in the UK top 30 websites

with over 7 million visitors a month*

Which means almost 1 in 5 UK internet users visit us every month

* Average unique visitors according to ComScore data in 2013

A place which connects people to the things they need…

• 1.7 million live adverts

• 150 million adverts posted in all time

• 100,000 new adverts per day

• Approx 300,000 replies per day

Source: Gumtree data, November 2013

Gumtree Tech

Gumtree Tech

• 15 Back End devs• 6 Front End devs• 3 Mobile App devs• 5 Site Ops• 5 Product Managers• 6 QA• 3 Designers

Redis

RiakCassandra

mongoDBCouchDB

Neo4j

•Replies

•Sessions

•A few other things

Replies

v.1Mail

ServerMail

Server

REST API

Anony-mizer

CassandraMy

SQL

MobileApps

• OSGI

• Two sources of truth?!

MySQL MySQL

Scalability?

Cassandra

?

‘We need something better’

v.2Mail

ServerMail

Server

REST API

Anony-mizer

ElasticSearch

RIAK

MobileApps

‘Just a Key-Value Store’

• Real-time Querying?

• Reporting?

• My manager wants to know how many of x happened in y?

“But all of this

works fine in

MySQL…”

Use the Right Tool

for the Right Job

The German Story

Using iak for ReplyTS

15TB

18Nodes

2Data

centers

And then we Launched.

And everything was fine!

Well, at least 3 Months…

alwaysNew Technology

fails!

Backup... and if you can’t: have a backup plan

Have a

Dear Basho Devs,

So where are Gumtree in all this?

• Keeping a close eye on eBay Kleinanzeigen’s experiences

• Acknowledging that staying with the MySQL and Cassandra solution, is not suitable for Gumtree’s long term needs

Sessions

Richard

Gumtree servers

Interweb

Improving support for regular software releases

Oh… That’s not good.

• Off-peak release times only

• Sticky sessions have a lot to answer for

• Have to restart instance => Kill everyone on it

redis

Redis

• ‘Just another key-value store’

• Data typing

• TTL support

• Support for master-slave, monitoring, publish-subscribe

Richard

Gumtree servers

Interweb

Success!

Redis

Redis – all good?• Single master = single point of failure

• Sentinel – potential 66 seconds of downtime when master fails?

• Sharding is never easy

• Not tested dual data centre setup

The Other Stuff

mongoDB

• Popular Search Tracking

– High realtime write-traffic

– Regretting this a lot

• Some low traffic use cases

– Low traffic, low read

• Some batch event analysis

– Batched reads and writes

In Conclusion

• Data consistency vs. High availability

• NoSQL comes in many different guises, technologies suited for different use cases

• No technology is perfect

If you enjoyed this talk and like Gumtree

• eBay Tech Meetups across Europe– http://www.meetup.com/eBay-Europe-Technology

• Gumtree Careers via LinkedIn– http://linkd.in/1eu4rK5

Thank You!

…Questions or comments?