Making notes here about ways to optimize connections via apache. I was reading through some sources about apache worker concurrency (since CPU usage seems to be a bottleneck? at least that's an operative theory), here's an informative one:

https://serverfault.com/questions/775855/how-to-configure-apache-workers-for-maximum-concurrency

So I need to find out which modules are being loaded and what settings are being used. Here's the setup for dev2 and playground (AWS).

gracedb-dev2:

root@gracedb-dev2:/etc/apache2# apachectl -M | grep mpm
 mpm_worker_module (shared)

root@gracedb-dev2:/etc/apache2# cat mods-enabled/worker.conf
<IfModule mpm_worker_module>
  ServerLimit         25
  StartServers        2
  ThreadLimit         64
  MaxClients          150
  MinSpareThreads     25
  MaxSpareThreads     75
  ThreadsPerChild     25
  MaxRequestsPerChild 0
  ListenBacklog       511
</IfModule>

gracedb-playground:

root@17b0c88a4c4f:/etc/apache2# apachectl -M | grep mpm
 mpm_event_module (shared)

root@17b0c88a4c4f:/etc/apache2# cat mods-enabled/mpm_event.conf
# event MPM
# StartServers: initial number of server processes to start
# MinSpareThreads: minimum number of worker threads which are kept spare
# MaxSpareThreads: maximum number of worker threads which are kept spare
# ThreadsPerChild: constant number of worker threads in each server process
# MaxRequestWorkers: maximum number of worker threads
# MaxConnectionsPerChild: maximum number of requests a server process serves
<IfModule mpm_event_module>
	StartServers			 2
	MinSpareThreads		 25
	MaxSpareThreads		 75
	ThreadLimit			 64
	ThreadsPerChild		 25
	MaxRequestWorkers	  150
	MaxConnectionsPerChild   0
</IfModule>

# vim: syntax=apache ts=4 sw=4 sts=4 sr noet

So that's a start at least. They look to be the same (I'm assuming the default...), but i have some knobs to tweak potentially. I'll look into doing some testing with ab and siege and see what i can come up with.