diff --git a/lib/jobs/enqueue_digest_emails.rb b/lib/jobs/enqueue_digest_emails.rb
index a19e35119e7..651156ff6b6 100644
--- a/lib/jobs/enqueue_digest_emails.rb
+++ b/lib/jobs/enqueue_digest_emails.rb
@@ -5,15 +5,14 @@ module Jobs
     recurrence { daily.hour_of_day(6) }
 
     def execute(args)
-      target_users.each do |u|
-        Jobs.enqueue(:user_email, type: :digest, user_id: u.id)
+      target_user_ids.each do |user_id|
+        Jobs.enqueue(:user_email, type: :digest, user_id: user_id)
       end
     end
 
-    def target_users
+    def target_user_ids
       # Users who want to receive emails and haven't been emailed in the last day
-      query = User.select(:id)
-                  .where(email_digests: true, active: true)
+      query = User.where(email_digests: true, active: true)
                   .where("COALESCE(last_emailed_at, '2010-01-01') <= CURRENT_TIMESTAMP - ('1 DAY'::INTERVAL * digest_after_days)")
                   .where("COALESCE(last_seen_at, '2010-01-01') <= CURRENT_TIMESTAMP - ('1 DAY'::INTERVAL * digest_after_days)")
 
@@ -22,7 +21,7 @@ module Jobs
         query = query.where("approved OR moderator OR admin")
       end
 
-      query
+      query.pluck(:id)
     end
 
   end
diff --git a/spec/components/jobs/enqueue_digest_emails_spec.rb b/spec/components/jobs/enqueue_digest_emails_spec.rb
index 15900f04abc..4825ad1acf6 100644
--- a/spec/components/jobs/enqueue_digest_emails_spec.rb
+++ b/spec/components/jobs/enqueue_digest_emails_spec.rb
@@ -10,33 +10,33 @@ describe Jobs::EnqueueDigestEmails do
       let!(:user_no_digests) { Fabricate(:active_user, email_digests: false, last_emailed_at: 8.days.ago, last_seen_at: 10.days.ago) }
 
       it "doesn't return users with email disabled" do
-        Jobs::EnqueueDigestEmails.new.target_users.include?(user_no_digests).should be_false
+        Jobs::EnqueueDigestEmails.new.target_user_ids.include?(user_no_digests.id).should be_false
       end
     end
 
     context 'unapproved users' do
       Given!(:unapproved_user) { Fabricate(:active_user, approved: false, last_emailed_at: 8.days.ago, last_seen_at: 10.days.ago) }
       When { SiteSetting.stubs(:must_approve_users?).returns(true) }
-      Then { expect(Jobs::EnqueueDigestEmails.new.target_users.include?(unapproved_user)).to eq(false) }
+      Then { expect(Jobs::EnqueueDigestEmails.new.target_user_ids.include?(unapproved_user.id)).to eq(false) }
 
       # As a moderator
       And { unapproved_user.update_column(:moderator, true) }
-      And { expect(Jobs::EnqueueDigestEmails.new.target_users.include?(unapproved_user)).to eq(true) }
+      And { expect(Jobs::EnqueueDigestEmails.new.target_user_ids.include?(unapproved_user.id)).to eq(true) }
 
       # As an admin
       And { unapproved_user.update_attributes(admin: true, moderator: false) }
-      And { expect(Jobs::EnqueueDigestEmails.new.target_users.include?(unapproved_user)).to eq(true) }
+      And { expect(Jobs::EnqueueDigestEmails.new.target_user_ids.include?(unapproved_user.id)).to eq(true) }
 
       # As an approved user
       And { unapproved_user.update_attributes(admin: false, moderator: false, approved: true ) }
-      And { expect(Jobs::EnqueueDigestEmails.new.target_users.include?(unapproved_user)).to eq(true) }
+      And { expect(Jobs::EnqueueDigestEmails.new.target_user_ids.include?(unapproved_user.id)).to eq(true) }
     end
 
     context 'recently emailed' do
       let!(:user_emailed_recently) { Fabricate(:active_user, last_emailed_at: 6.days.ago) }
 
       it "doesn't return users who have been emailed recently" do
-        Jobs::EnqueueDigestEmails.new.target_users.include?(user_emailed_recently).should be_false
+        Jobs::EnqueueDigestEmails.new.target_user_ids.include?(user_emailed_recently.id).should be_false
       end
     end
 
@@ -44,7 +44,7 @@ describe Jobs::EnqueueDigestEmails do
       let!(:inactive_user) { Fabricate(:user) }
 
       it "doesn't return users who have been emailed recently" do
-        Jobs::EnqueueDigestEmails.new.target_users.include?(inactive_user).should be_false
+        Jobs::EnqueueDigestEmails.new.target_user_ids.include?(inactive_user.id).should be_false
       end
     end
 
@@ -53,7 +53,7 @@ describe Jobs::EnqueueDigestEmails do
       let!(:user_visited_today) { Fabricate(:active_user, last_seen_at: 6.days.ago) }
 
       it "doesn't return users who have been emailed recently" do
-        Jobs::EnqueueDigestEmails.new.target_users.include?(user_visited_today).should be_false
+        Jobs::EnqueueDigestEmails.new.target_user_ids.include?(user_visited_today.id).should be_false
       end
     end
 
@@ -62,7 +62,7 @@ describe Jobs::EnqueueDigestEmails do
       let!(:user) { Fabricate(:active_user) }
 
       it "returns the user" do
-        Jobs::EnqueueDigestEmails.new.target_users.should == [user]
+        Jobs::EnqueueDigestEmails.new.target_user_ids.should == [user.id]
       end
     end
 
@@ -73,7 +73,7 @@ describe Jobs::EnqueueDigestEmails do
     let(:user) { Fabricate(:user) }
 
     before do
-      Jobs::EnqueueDigestEmails.any_instance.expects(:target_users).returns([user])
+      Jobs::EnqueueDigestEmails.any_instance.expects(:target_user_ids).returns([user.id])
     end
 
     it "enqueues the digest email job" do