The default wakeup interval is defined to be 5000 ms.
When adding a large amount of data to the cache, purging will block the whole application, because it starts - runs for a long time - stops and will be again started immediatly.
This leads to a "logical infinite loop" blocking the application.
This will get even worse when parallel purging (multiThreadedPugre / purgerThreads) is used)
This is legacy, when the thread was intended to handle eviction as well. Now that the thread only takes care of expiry, there is no need for this default to be this short. A more sensible default (60s) is used instead.