diff --git a/lib/mix/tasks/pleroma/database.ex b/lib/mix/tasks/pleroma/database.ex
index 396536827..6f4c3b3c4 100644
--- a/lib/mix/tasks/pleroma/database.ex
+++ b/lib/mix/tasks/pleroma/database.ex
@@ -113,36 +113,13 @@ defmodule Mix.Tasks.Pleroma.Database do
     Logger.info(log_message)
 
     if Keyword.get(options, :keep_threads) do
-      # We want to delete objects from threads where
-      # 1. the newest post is still old
-      # 2. none of the activities is local
-      # 3. none of the activities is bookmarked
-      # 4. optionally none of the posts is non-public
+      # Delete objects from threads that nobody local interacted with and that
+      # have been quiet for longer than the retention period, see Pleroma.Retention.
       deletable_context =
-        if Keyword.get(options, :keep_non_public) do
-          Pleroma.Activity
-          |> join(:left, [a], b in Pleroma.Bookmark, on: a.id == b.activity_id)
-          |> group_by([a], fragment("? ->> 'context'::text", a.data))
-          |> having(
-            [a],
-            not fragment(
-              # Posts (checked on Create Activity) is non-public
-              "bool_or((not(?->'to' \\? ? OR ?->'cc' \\? ?)) and ? ->> 'type' = 'Create')",
-              a.data,
-              ^Pleroma.Constants.as_public(),
-              a.data,
-              ^Pleroma.Constants.as_public(),
-              a.data
-            )
-          )
-        else
-          Pleroma.Activity
-          |> join(:left, [a], b in Pleroma.Bookmark, on: a.id == b.activity_id)
-          |> group_by([a], fragment("? ->> 'context'::text", a.data))
-        end
-        |> having([a], max(a.updated_at) < ^time_deadline)
-        |> having([a], not fragment("bool_or(?)", a.local))
-        |> having([_, b], fragment("max(?::text) is null", b.id))
+        time_deadline
+        |> Pleroma.Retention.evictable_contexts_query(
+          keep_non_public: Keyword.get(options, :keep_non_public)
+        )
         |> select([a], fragment("? ->> 'context'::text", a.data))
 
       Pleroma.Object
@@ -222,18 +199,7 @@ defmodule Mix.Tasks.Pleroma.Database do
       |> Repo.query([], timeout: :infinity)
     end
 
-    """
-    DELETE FROM hashtags AS ht
-    WHERE NOT EXISTS (
-      SELECT 1 FROM hashtags_objects hto
-      WHERE ht.id = hto.hashtag_id
-    )
-    AND NOT EXISTS (
-      SELECT 1 FROM user_follows_hashtag ufh
-      WHERE ht.id = ufh.hashtag_id
-    )
-    """
-    |> Repo.query()
+    Pleroma.Retention.delete_unused_hashtags()
 
     if Keyword.get(options, :vacuum) do
       Maintenance.vacuum("full")
diff --git a/test/mix/tasks/pleroma/database_test.exs b/test/mix/tasks/pleroma/database_test.exs
index 0f38891b4..b3f25130c 100644
--- a/test/mix/tasks/pleroma/database_test.exs
+++ b/test/mix/tasks/pleroma/database_test.exs
@@ -200,6 +200,23 @@ defmodule Mix.Tasks.Pleroma.DatabaseTest do
       refute Object.get_by_ap_id(old_remote_post2_id)
     end
 
+    test "with the --keep-threads option it keeps old threads that mentioned a local user", %{
+      old_insert_date: old_insert_date
+    } do
+      remote_user = insert(:user, local: false)
+      local_user = insert(:user)
+
+      {:ok, activity} = CommonAPI.post(remote_user, %{status: "hey @#{local_user.nickname}"})
+
+      activity
+      |> Ecto.Changeset.change(%{local: false, updated_at: old_insert_date})
+      |> Repo.update!()
+
+      Mix.Tasks.Pleroma.Database.run(["prune_objects", "--keep-threads"])
+
+      assert Object.get_by_ap_id(activity.data["object"])
+    end
+
     test "with the --keep-threads option it still keeps non-old threads even with no local interactions" do
       remote_user = insert(:user, local: false)
       remote_user2 = insert(:user, local: false)