fix: add indexes for invitation queries and optimize event count

- Add composite indexes on (member_id, attending) and (event_id, attending)
  for workshop_invitations, meeting_invitations, and invitations tables
- Replace inefficient total_upcoming_events_count that loaded all workshops
  with simple COUNT queries

Author: mroderick

app/controllers/dashboard_controller.rb

@@ -79,8 +79,11 @@ def upcoming_events
   end
 
   def total_upcoming_events_count
-    workshops = Workshop.eager_load(:chapter, :sponsors, :organisers, :permissions)
-    all_events(workshops.to_a).count
+    workshop_count = Workshop.upcoming.count
+    event_count = Event.upcoming.count
+    meeting_exists = Meeting.next.present? ? 1 : 0
+
+    workshop_count + event_count + meeting_exists
   end
 
   def upcoming_events_for_user

db/migrate/20260224120000_add_indexes_for_invitation_queries.rb

@@ -0,0 +1,12 @@
+class AddIndexesForInvitationQueries < ActiveRecord::Migration[8.1]
+  def change
+    add_index :workshop_invitations, %i[member_id attending], name: 'index_workshop_invitations_member_attending'
+    add_index :workshop_invitations, %i[workshop_id attending], name: 'index_workshop_invitations_workshop_attending'
+
+    add_index :meeting_invitations, %i[member_id attending], name: 'index_meeting_invitations_member_attending'
+    add_index :meeting_invitations, %i[meeting_id attending], name: 'index_meeting_invitations_meeting_attending'
+
+    add_index :invitations, %i[member_id attending], name: 'index_invitations_member_attending'
+    add_index :invitations, %i[event_id attending], name: 'index_invitations_event_attending'
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.1].define(version: 2026_02_11_140256) do
+ActiveRecord::Schema[8.1].define(version: 2026_02_24_120000) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_catalog.plpgsql"
 
@@ -298,7 +298,9 @@
     t.datetime "updated_at", precision: nil
     t.boolean "verified"
     t.integer "verified_by_id"
+    t.index ["event_id", "attending"], name: "index_invitations_event_attending"
     t.index ["event_id"], name: "index_invitations_on_event_id"
+    t.index ["member_id", "attending"], name: "index_invitations_member_attending"
     t.index ["member_id"], name: "index_invitations_on_member_id"
     t.index ["verified_by_id"], name: "index_invitations_on_verified_by_id"
   end
@@ -338,7 +340,9 @@
     t.string "role"
     t.string "token"
     t.datetime "updated_at", precision: nil
+    t.index ["meeting_id", "attending"], name: "index_meeting_invitations_meeting_attending"
     t.index ["meeting_id"], name: "index_meeting_invitations_on_meeting_id"
+    t.index ["member_id", "attending"], name: "index_meeting_invitations_member_attending"
     t.index ["member_id"], name: "index_meeting_invitations_on_member_id"
   end
 
@@ -547,8 +551,10 @@
     t.text "tutorial"
     t.datetime "updated_at", precision: nil
     t.integer "workshop_id"
+    t.index ["member_id", "attending"], name: "index_workshop_invitations_member_attending"
     t.index ["member_id"], name: "index_workshop_invitations_on_member_id"
     t.index ["token"], name: "index_workshop_invitations_on_token", unique: true
+    t.index ["workshop_id", "attending"], name: "index_workshop_invitations_workshop_attending"
     t.index ["workshop_id"], name: "index_workshop_invitations_on_workshop_id"
   end