fix: resolve N+1 query in ConfigReport.summarise

[raman1236]

Description

Resolves the N+1 query in ConfigReport.summarise that has been marked with a TODO comment since the method was written.

Problem

The summarise method performed one SQL query per host to fetch recent reports:

hosts.flatten.each do |host|
  host.reports.recent(time).select(:status).each do |r|
    # ...
  end
end

For a page listing 100 hosts, this generates 100 separate queries.

Fix

Replaced the per-host queries with a single batch query that loads all reports at once:

hosts_by_id = hosts.flatten.index_by(&:id)
reports_by_host = ConfigReport.where(:host_id => hosts_by_id.keys)
                              .recent(time)
                              .select(:host_id, :status)
                              .group_by(&:host_id)

The reports are then grouped by host_id in Ruby, maintaining the same behavior while reducing database round-trips from N+1 to 1.

[ofedoren]

Thanks, @raman1236, could you please create a new ticket (https://projects.theforeman.org/projects/foreman/issues/new) and use its number in commit message? Also, small question inline.

[raman1236]

Friendly ping — this PR resolves an N+1 query in ConfigReport.summarise by eager loading the associated records. Would appreciate a review when you have a moment. Thanks!

[adamruzicka]

Friendly ping

There is an unanswered question from three weeks ago (comment) and the commit message wasn't reworded as requested either (comment). The ball is in your court