I can not understand, graphite support udp, why do we need statsd

Question

Graphite can user TCP and UDP lisen,why graphite default use TCP not UDP.Whether statsd is superfluous?

Answer 1

StatsD also does aggregation of metrics. For example, you can send it 1000s of timing events and then every flush interval (default 10 seconds) it will calculate summary statistics for that timer including mean, upper, lower, count, count per second etc. Therefore I would argue that StatsD is not superfluous as it has additional features to Graphite.