In many instances the terms `big data` and `Hadoop` are reserved for conversations on business analytics. Instead, I posit that these technologies are most powerful when they are deployed as a way to both build new products, and improve existing ones. Measurement is a fundamental part of the process, but more importantly I will walk through an effective tool-chain that can be used to: a) build unique new products, based on data. b) test improvements to a product At Foursquare, we`ve used a Hadoop-based tool chain to build new products (like social-recommendations), and to improve existing features through initiatives such as experimentation, and offline data generation. These products and improvements are fundamental to our core business, yet their existence would not be possible without Hadoop. I will pull examples from Foursquare and other companies to demonstrate these points, and outline the infrastructure components needed to accomplish them.
2. 2013
What is Foursquare
Foursquare helps you explore
the world around you.
Meet up with friends, discover
new places, and save money
using your phone.
4bn check-ins
35mm users
50mm POI
150 employees
1tb+ a day of data
4. 2013
The Right Tool for the Job
• Nginx – Serving static files
• Perl – Regular expressions
• XML – Frustrating people
• Hadoop (Map Reduce) – Counting
14. 2013
SIPS
• Tokenize data with a language model (into N-
Grams)
• built using tips, shouts, menu items, likes, etc
• Apply a TF-IDF algorithm (Term frequency,
inverse document frequency)
• Global phrase count
• Local phrase count ( in a venue )
• Some Filtering and ranking
• Re-compute & deploy nightly
16. 2013
SIPS – Without Hadoop
Potential Problems
• Database Query Throttling
• Venues are out of sync
• Altering the algorithm could take forever to
populate for all venues
• Where would you store the results?
• What about debug data?
• Does it scale to 10x, 100x?
• What about other, similar workflows?
17. 2013
SIPS – Hadoop Benefits
• Quick Deployment
• Modular & Reusable
• Arbitrarily complex combination of many
datasets
• Every step of the workflow creates value
18. 2013
Apple Store - Downtown San Francisco
1 tip mentions "haircuts"
Search for "haircuts" in "san francisco" Apple store???
Fixed by looking at % of tips and overall frequency
“Hey Apple, how bout less shiny pizzazz and fancy haircuts and more fix-
my-f!@#$-imac”
29. 2013
MapReduce Friendly Datastore
A few obvious ones:
• Hbase
• Cassandra
• Voldemort
we built our own, it’s very similar to
Voldemort and uses the Hfile API
34. 2013
Other reasons to not use Hadoop
• Your idea might not be very good
• Hadoop will slow you down to start with
• You don’t have enough infrastructure yet
• build it when you need it
• V1 might not be that complex
• V1 could be a spreadsheet
37. 2013
SIPS
Version 1
• Off the shelf language model
• A subset of Venues & Tips
• Did not use Map Reduce
• Did not push to production at all
38. 2013
SIPS
Version 2
• Started building our own language model
• Rewritten as a Map Reduce
• Manually loaded data to production
• Filters for English data only.
Tweak, improve, etc
39. 2013
SIPS
Version 3
• Incorporated more data sources into our language
model
• Deployment to KV store (auto)
• Incorporated lots of debug output
• Language pipeline also feeds sentiment analysis
Now we’re in the perfect place to iterate & improve
41. 2013
In Summary
• Hadoop is good for counting, so use it for
counting
• Move quickly whenever possible and don’t
worry about automation
• Bring in new production services as you
need them
• Freedom!
Friend – financeSpent 2 years building management platformScrapped the projectFund manager hired kid to build excel macrosRight tool for the job
Great for analyticsGreat for your products too
- tf-idf : counting globally, counting locally
Use lots of data sources without fearEach MR step outputs data to hdfs that can be used in other workflows.Makes the workflow naturally modulareasy to test isolated parts of the workflow
Once you’ve solved the MR -> Datastore problem once, you’ve solved it for good.
Every task has requirementsOther tasksDirectories with _SUCCESS flagsRun on cron
- Hadoop-friendly Datastore-- we built our own (HFile Service)-- -- immutable-- -- downloads data from s3-- -- reads everything into memory (but doesn't need to)-- -- create X shards using map-reduce, swap these into X servers. They memory-map the files
when in production hadoop lets you iterate quicklyright now, it slows you downstill work offlinedo it without any of the important components I just told you about
build a MVP in a spreadsheet, webview, whatevereven if you deploy it, you can manually load data into a DB to start withIf you’re testing a v1 for a limited subset (employees), you probably don’t have much data anyway
This didn’t need any of the key infrastructure components
This needed database dumps.Ran on a cronLoaded manually
Needed database dumpsRun with our dependency management engineLoads to our production datastore