Use more efficient user note count update query.

lib/pleroma/user.ex

@@ -241,7 +241,7 @@ defmodule Pleroma.User do
 
   def update_note_count(%User{} = user) do
     note_count_query = from a in Object,
-      where: fragment("? @> ?", a.data, ^%{actor: user.ap_id, type: "Note"}),
+      where: fragment("?->>'actor' = ? and ?->>'type' = 'Note'", a.data, ^user.ap_id, a.data),
       select: count(a.id)
 
     note_count = Repo.one(note_count_query)

priv/repo/migrations/20171024121413_add_object_actor_index.exs

@@ -0,0 +1,9 @@
+defmodule Pleroma.Repo.Migrations.AddObjectActorIndex do
+  use Ecto.Migration
+
+  @disable_ddl_transaction true
+
+  def change do
+    create index(:objects, ["(data->>'actor')", "(data->>'type')"], concurrently: true, name: :objects_actor_type)
+  end
+end