def pickle_cache(mode="auto"):
    
    def pc_decorator(func):

        def pc_wrapper(*args, **kwargs):
            cache_fp = Path(PROXY_DIR, f"{func.__name__}.pickle")
            today = dt.date.today()
            if cache_fp.exists():
                statinfo = cache_fp.stat()
                # (st_mode, st_ino, st_dev, st_nlink, st_uid, st_gid, st_size, st_atime, st_mtime, st_ctime) = statinfo
                (_, _, _, _, _, _, _, _, st_mtime, _) = statinfo
                mdate = dt.datetime.fromtimestamp(st_mtime).date()
            else:
                mdate = None
            if mode == "auto":
                if cache_fp.exists() and mdate == today:
                    action = "cached"
                else:
                    action = "query"
            else:
                action = mode
            if action == "cached" :
                LOG.info(f"{func.__name__}: loading cached data...")
                with cache_fp.open("rb") as fh:
                    rc = pickle.load(fh)
            elif action == "query":
                LOG.info(f"{func.__name__}: database access...")
                rc = func(*args, **kwargs)
                if cache_fp.exists() and mdate != today and Path(PROXY_DIR, "Archive").exists():
                    archive_fp = Path(PROXY_DIR, "Archive", f"{func.__name__}-{mdate:%Y%m%d}.pickle")
                    shutil.copy(cache_fp, archive_fp)
                with cache_fp.open("wb") as fh:
                    pickle.dump(rc, fh)
            else:
                LOG.error(f"{func.__name__}: mode {action} unknown")
            return rc

        return pc_wrapper

    return pc_decorator