Only trigger refresh_instances when the actor being changed is a relay

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

priv/repo/migrations/20220505091224_change_refresh_instance_trigger_to_only_execute_on_relays.exs

@@ -0,0 +1,45 @@
+defmodule Mobilizon.Storage.Repo.Migrations.ChangeRefreshInstanceTriggerToOnlyExecuteOnRelays do
+  use Ecto.Migration
+
+  def up do
+    execute("""
+    DROP TRIGGER IF EXISTS refresh_instances_trigger ON actors;
+    """)
+
+    execute("""
+    CREATE TRIGGER refresh_instances_trigger_new
+    AFTER INSERT OR UPDATE
+    ON actors
+    FOR EACH ROW
+    WHEN (NEW.preferred_username = 'relay')
+    EXECUTE PROCEDURE refresh_instances();
+    """)
+
+    execute("""
+    CREATE TRIGGER refresh_instances_trigger_old
+    AFTER DELETE
+    ON actors
+    FOR EACH ROW
+    WHEN (OLD.preferred_username = 'relay')
+    EXECUTE PROCEDURE refresh_instances();
+    """)
+  end
+
+  def down do
+    execute("""
+    DROP TRIGGER IF EXISTS refresh_instances_trigger_new ON actors;
+    """)
+
+    execute("""
+    DROP TRIGGER IF EXISTS refresh_instances_trigger_old ON actors;
+    """)
+
+    execute("""
+    CREATE TRIGGER refresh_instances_trigger
+    AFTER INSERT OR UPDATE OR DELETE
+    ON actors
+    FOR EACH STATEMENT
+    EXECUTE PROCEDURE refresh_instances();
+    """)
+  end
+end