_db.py

@@ -16,6 +16,6 @@ real connection opens only when a query actually executes.
 """
 from __future__ import annotations
 
-from app.db.mariadb import run_select_query  # noqa: F401  (kernel SELECT-only proxy)
+from app.db.mariadb import run_select_query, cached_select  # noqa: F401  (kernel read proxies)
 
-__all__ = ["run_select_query"]
+__all__ = ["run_select_query", "cached_select"]

api/routes.py

@@ -46,7 +46,7 @@ from typing import Any, Optional
 
 from fastapi import APIRouter, Query
 
-from .._db import run_select_query
+from .._db import run_select_query, cached_select
 
 logger = logging.getLogger(__name__)
 
@@ -128,8 +128,11 @@ def _group_carts(rows: list[dict[str, Any]], colors: dict[str, int]) -> "dict[st
 
 
 def _fetch_presses(plant: str) -> list[str]:
+    # Reference data (admin-edited), re-read on every 12s poll — served from the shared
+    # reference cache so it stops consuming a pool checkout each poll.
     try:
-        rows = run_select_query(
+        rows = cached_select(
+            f"tov:presses:{plant}",
             "SELECT psPress AS press FROM press_settings.presses WHERE psPlant = :plant "
             "ORDER BY CAST(psPress AS UNSIGNED), psPress",
             {"plant": plant},
@@ -239,8 +242,10 @@ def _fetch_downtime_reasons(plant: str) -> dict[str, int]:
 
 
 def _fetch_reason_texts() -> dict[int, str]:
+    # Reference data (admin-edited), full-table read on every poll — served from cache.
     try:
-        rows = run_select_query(
+        rows = cached_select(
+            "tov:reason_texts",
             "SELECT id, reason_DE AS de FROM settings.downtime_reasons", {}
         )
     except Exception as e:  # noqa: BLE001