Description of problem:
Environment: Satellite 6.1.8 on RHEL 7.2, three virt-who instances (running on the Capsules) report Hypervisor/Guest mappings from 5 VMware vCenters (virt-who-01: 488 hypervisors / 11224 guests + 14 hypervisors / 322 guests, virt-who-02: 399 hypervisors / 8379 guests + 7 hypervisors / 147 guests, virt-who-03: 488 hypervisors / 18468 guests).
PostgreSQL is as installed by katello-installer, the only change was to set max_stack_depth to 3M after we hit https://bugzilla.redhat.com/show_bug.cgi?id=1280346

When the virt-who instances are running, we see three PostgreSQL processes on the Satellite taking one CPU core each. Stopping one virt-who will reduce the number of busy PostgreSQL processes by one.

Looking at pg_stat_activity for such a process yields the following (this particular one was running for ~3minutes):
postgres=# select * from pg_stat_activity where pid = 5345;
-[ RECORD 1 ]----+-
datid            | 16387
datname          | candlepin
pid              | 5345
usesysid         | 16386
usename          | candlepin
application_name |
client_addr      | 127.0.0.1
client_hostname  |
client_port      | 52114
backend_start    | 2016-04-13 15:08:33.113219+02
xact_start       | 2016-04-13 15:53:52.538085+02
query_start      | 2016-04-13 15:53:57.05335+02
state_change     | 2016-04-13 15:53:57.053385+02
waiting          | f
state            | active
query            | select this_.consumer_id as y0_ from cp_consumer_guests this_ inner join cp_consumer gconsumer1_ on this_.consumer_id=gconsumer1_.id inner join cp_guest_ids_checkin checkins2_ on gconsumer1_.id=checkins2_.consumer_id where gconsumer1_.owner_id=$1 and (lower(this_.guest_id)=$2 or lower(this_.guest_id)=$3 or lower(this_.guest_id)=$4 or lower(this_.guest_id)=$5 or lower(this_.guest_id)=$6 or lower(this_.guest_id)=$7 or lower(this_.guest_id)=$8 or lower(this_.guest_id)=$9 or lower(this_.guest_id)=$10 or lower(this_.guest_id)=$11 or lower(this_.guest_id)=$12 or lower(this_.guest_id)=$13 or lower(this_.guest_id)=$14 or lower(this_.guest_id)=$15 or lower(this_.guest_id)=$16 or lower(this_.guest_id)=$17 or lower(this_.guest_id)=$18 or lower(this_.guest_id)=$19 or lower(this_.guest_id)=$20 or lower(this_.guest_id)=$21 or lower(this_.guest_id)=$22 or lower(this_.guest_id)=$23 or lower(this_.guest_id)=$24 or lower(this_.guest_id)=$25 or lower(this_.guest_id)=$26 or lower(this_.guest_id)=$27 or lower(this_.guest_id)=$28

Version-Release number of selected component (if applicable):
6.1.8

How reproducible:
always

Steps to Reproduce:
1. Install Satellite 6.1.8
2. let virt-who report big hypervisor/guest mappings to it

Actual results:
for each virt-who instance we see one highly loaded PostgreSQL process, executing slow queries

Expected results:
better performance :)