Do web services written in Clojure perform as well as those written in Java? We put this modest 5 node cluster to the load test on EC2 just to see what it could take.

1. Clojure Performance
Measuring throughput
and latency
Of a news feed
Web service
Written in Clojure

2. Features
●
Participant Profiles
●
Social Graph
●
Social Broadcast
●
Inbound Activity
●
Outbound Activity
●
Keyword Search

3. Components
●
Postgresql
●
Cassandra
●
Solr
●
Kafka
●
Redis
●
Jetty

4. Source Code
●
https://github.com/gengstrand/clojure-newsfeed

5. AWS Deployment
●
Ubuntu Server 12.04.3 LTS 64 bit
●
Servers (no provisioned IOPs)
–
●
Database (RDS)
–
●
m1.medium (2 ECUs, 1 vCPUs, 3.7 GiB
memory, 1 x 410 GiB Storage Capacity)
db.m1.medium
Client Load Machine
–
m1.large (4 ECUs, 2 vCPUs, 7.5 GiB
memory, 2 x 420 GiB Storage Capacity)

6. Throughput

7. Throughput
●
100 threads
●
Connection pool max size: 50
●
5 < Social Broadcast < 50
●
10 posts per user
●
10% searches
●
55 posts per second

8. Latency Overall
●
Poor at the beginning – cold cache
●
Really good 15 minutes in
●
Bad spike near the end of the first hour
●
Steady performance in the second hour

9. Postgresql Latency

10. Cassandra Latency

11. Solr Latency

12. Web Service Latency

13. Summary
●
Cloud Spike
●
Postgresql latency similar to Cassandra
●
Solr indexing twice as slow
●
Between 50 and 70 requests per second
●
Clojure just as fast as Java
●
Jetty performed well

14. Thanks
Glenn Engstrand