Correlate TargetResponseTime with Aurora's long_query_time

[kaihendry]

https://s.natalian.org/2018-04-19/latency.mp4 just cared to monitor TargetResponseTime.

Using Aurora should allows us to plot metrics of queries taking a long time. I am assuming this is the cause of long TargetResponseTimes reported by the ECS load balancer on Bugzilla.

Then we can hopefully drill down the troublesome queries.

[kaihendry]

Hopefully an see the slow queries with select sleep(10);.

[kaihendry]

From my investigations here: https://github.com/unee-t/whyslow

It would appear AuroraDB is not slow. There is some bottle neck in process_bug.cgi in the Bugzilla side.