Fixes #18893 - Improve latest events widget performance

theforeman · Mar 23, 2017 · 9313f6a · 9313f6a
1 parent 9ca77d0
commit 9313f6a
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Showing 3 changed files with 14 additions and 2 deletions.
diff --git a/app/services/dashboard/data.rb b/app/services/dashboard/data.rb
@@ -27,7 +27,14 @@ def latest_events
     @latest_events ||= ConfigReport.authorized(:view_config_reports).my_reports.interesting
                                    .where("#{ConfigReport.quoted_table_name}.#{con.quote_column_name('host_id')} IN (#{ids})")
                                    .search_for('reported > "7 days ago"')
-                                   .limit(9).includes(:host)
+                                   .reorder(:reported_at => :desc)
+                                   .limit(9)
+                                   .preload(:host)
+  end
+
+  def latest_events?
+    #exists? removes the order field causing the db to use the wrong index
+    latest_events.limit(1).present?
   end
 
   private

diff --git a/app/views/dashboard/_reports_widget.html.erb b/app/views/dashboard/_reports_widget.html.erb
@@ -1,7 +1,7 @@
 <h4 class="header">
   <%= _("Latest Events") %>
 </h4>
-<% if @data.latest_events.exists? %>
+<% if @data.latest_events? %>
   <table class="<%= table_css_classes 'table-fixed reports-table' %>">
     <thead>
       <tr>

diff --git a/db/migrate/20170315154334_add_report_time_type_host_index.rb b/db/migrate/20170315154334_add_report_time_type_host_index.rb
@@ -0,0 +1,5 @@
+class AddReportTimeTypeHostIndex < ActiveRecord::Migration
+  def change
+    add_index :reports, [:reported_at, :host_id, :type]
+  end
+end