diff --git a/bot.py b/bot.py
index 65c35b0..7fb51a0 100644
--- a/bot.py
+++ b/bot.py
@@ -251,7 +251,7 @@ def main() -> None:
 
             except Exception as e:
                 print(f"[loop] error for {sym}: {e}")
-
+        print(f"[heartbeat] {dt.datetime.utcnow().isoformat()}Z")
         time.sleep(2)
 
 
diff --git a/storage.sqlite-shm b/storage.sqlite-shm
deleted file mode 100644
index fe9ac28..0000000
Binary files a/storage.sqlite-shm and /dev/null differ
diff --git a/storage.sqlite-wal b/storage.sqlite-wal
deleted file mode 100644
index e69de29..0000000