Regarding that too many items can overload the server, and may take too many time to being cached Warmup table can be limited. Default limit is 10 000 items, it can be modified by defining a constant in wp-config.php

To modify limit just insert the following code to wp-config.php (before the /* That’s all, stop editing! Happy blogging. */ part)

define('SWIFT_PERFORMANCE_WARMUP_LIMIT', 20000);