Migrations: Change object index on activities

This will now only index create activities.

priv/repo/migrations/20201115114437_change_object_index_on_create_activities.exs

@@ -0,0 +1,22 @@
+defmodule Pleroma.Repo.Migrations.ChangeObjectIndexOnCreateActivities do
+  use Ecto.Migration
+
+  @disable_ddl_transaction true
+  @disable_migration_lock true
+
+  def change do
+    drop_if_exists(
+      index(:activities, ["(coalesce(data->'object'->>'id', data->>'object'))"],
+        name: :activities_create_objects_index
+      )
+    )
+
+    create(
+      index(:activities, ["(coalesce(data->'object'->>'id', data->>'object'))"],
+        name: :activities_create_objects_index,
+        concurrently: true,
+        where: "data->>'type' = 'Create'"
+      )
+    )
+  end
+end