Remove duplicate members before joining with users table

If there are duplicate members when joining with the users
table, it results in a lot of unnecessary memory usage.

The members table can contain the same user_id multiple times
if the user_id is part of multiple groups/projects. Currently, the
SQL query generated by Group#billed_project_members joins the
members and users tables. The duplicate user_ids in the members
table can result in unnecessary memory usage.
This commit modifies Group#billed_project_members to filter out
duplicate members rows first in a subquery, and the subquery is then
used as an IN condition to query the users table.

It also renames Group#billed_project_members to
Group#billed_project_users.

app/models/member.rb

@@ -108,10 +108,14 @@ class Member < ApplicationRecord
   scope :active_without_invites_and_requests, -> do
     left_join_users
       .where(users: { state: 'active' })
-      .non_request
+      .without_invites_and_requests
+      .reorder(nil)
+  end
+
+  scope :without_invites_and_requests, -> do
+    non_request
       .non_invite
       .non_minimal_access
-      .reorder(nil)
   end
 
   scope :invite, -> { where.not(invite_token: nil) }

ee/app/models/ee/group.rb

@@ -513,34 +513,34 @@ module EE
 
     def billed_user_ids_excluding_guests
       strong_memoize(:billed_user_ids_excluding_guests) do
-        group_member_ids = billed_group_members.non_guests.distinct.pluck(:user_id)
-        project_member_ids = billed_project_members.non_guests.distinct.pluck(:user_id)
-        shared_group_ids = billed_shared_non_guests_group_members.non_guests.distinct.pluck(:user_id)
-        shared_project_ids = billed_invited_non_guests_group_to_project_members.non_guests.distinct.pluck(:user_id)
+        group_member_user_ids = billed_group_members.non_guests.distinct.pluck(:user_id)
+        project_member_user_ids = billed_project_users(non_guests: true).distinct.pluck(:id)
+        shared_group_user_ids = billed_shared_non_guests_group_members.non_guests.distinct.pluck(:user_id)
+        shared_project_user_ids = billed_invited_non_guests_group_to_project_members.non_guests.distinct.pluck(:user_id)
 
         {
-          user_ids: (group_member_ids + project_member_ids + shared_group_ids + shared_project_ids).to_set,
-          group_member_user_ids: group_member_ids.to_set,
-          project_member_user_ids: project_member_ids.to_set,
-          shared_group_user_ids: shared_group_ids.to_set,
-          shared_project_user_ids: shared_project_ids.to_set
+          user_ids: (group_member_user_ids + project_member_user_ids + shared_group_user_ids + shared_project_user_ids).to_set,
+          group_member_user_ids: group_member_user_ids.to_set,
+          project_member_user_ids: project_member_user_ids.to_set,
+          shared_group_user_ids: shared_group_user_ids.to_set,
+          shared_project_user_ids: shared_project_user_ids.to_set
         }
       end
     end
 
     def billed_user_ids_including_guests
       strong_memoize(:billed_user_ids_including_guests) do
-        group_member_ids = billed_group_members.distinct.pluck(:user_id)
-        project_member_ids = billed_project_members.distinct.pluck(:user_id)
-        shared_group_ids = billed_shared_group_members.distinct.pluck(:user_id)
-        shared_project_ids = billed_invited_group_to_project_members.distinct.pluck(:user_id)
+        group_member_user_ids = billed_group_members.distinct.pluck(:user_id)
+        project_member_user_ids = billed_project_users.distinct.pluck(:id)
+        shared_group_user_ids = billed_shared_group_members.distinct.pluck(:user_id)
+        shared_project_user_ids = billed_invited_group_to_project_members.distinct.pluck(:user_id)
 
         {
-          user_ids: (group_member_ids + project_member_ids + shared_group_ids + shared_project_ids).to_set,
-          group_member_user_ids: group_member_ids.to_set,
-          project_member_user_ids: project_member_ids.to_set,
-          shared_group_user_ids: shared_group_ids.to_set,
-          shared_project_user_ids: shared_project_ids.to_set
+          user_ids: (group_member_user_ids + project_member_user_ids + shared_group_user_ids + shared_project_user_ids).to_set,
+          group_member_user_ids: group_member_user_ids.to_set,
+          project_member_user_ids: project_member_user_ids.to_set,
+          shared_group_user_ids: shared_group_user_ids.to_set,
+          shared_project_user_ids: shared_project_user_ids.to_set
         }
       end
     end
@@ -553,10 +553,18 @@ module EE
     end
 
     # Members belonging directly to Projects within Group or Projects within subgroups
-    def billed_project_members
-      ::ProjectMember.active_without_invites_and_requests.without_project_bots.where(
+    def billed_project_users(non_guests: false)
+      members = ::ProjectMember.without_invites_and_requests
+
+      members = members.non_guests if non_guests
+
+      user_ids = members.where(
         source_id: ::Project.joins(:group).where(namespace: self_and_descendants)
       )
+      .distinct
+      .select(:user_id)
+
+      ::User.with_state(:active).without_project_bot.where(id: user_ids)
     end
 
     # Members belonging to Groups invited to collaborate with Projects

spec/models/member_spec.rb

@@ -408,6 +408,20 @@ RSpec.describe Member do
       it { is_expected.not_to include @member_with_minimal_access }
     end
 
+    describe '.without_invites_and_requests' do
+      subject { described_class.without_invites_and_requests.to_a }
+
+      it { is_expected.to include @owner }
+      it { is_expected.to include @maintainer }
+      it { is_expected.not_to include @invited_member }
+      it { is_expected.to include @accepted_invite_member }
+      it { is_expected.not_to include @requested_member }
+      it { is_expected.to include @accepted_request_member }
+      it { is_expected.to include @blocked_maintainer }
+      it { is_expected.to include @blocked_developer }
+      it { is_expected.not_to include @member_with_minimal_access }
+    end
+
     describe '.connected_to_user' do
       subject { described_class.connected_to_user.to_a }