Druid vs SummingBird

Hi, what’s the difference between Druid and Twitter’s SummingBird?
They both seems to implement the Lambda architecture: having two legs one for batched data and a second one for real-time, and doing merges;



Druid is a distributed database and you can load data into Druid using batch or realtime pipelines. Summingbird is a data processing library that can run on platforms that support batching and realtime processing of data such as Hadoop and Storm.