Memcache maximum key expiration time

Question

What\'s memcached\'s maximum key expiration time?

If I don\'t provide an expiration time and the cache gets full, what happens?

Answer 1

If you don't provide expiration and cache gets full then the oldest key-values are expired first:

Memory is also reclaimed when it's time to store a new item. If there are no free chunks, and no free pages in the appropriate slab class, memcached will look at the end of the LRU for an item to "reclaim". It will search the last few items in the tail for one which has already been expired, and is thus free for reuse. If it cannot find an expired item however, it will "evict" one which has not yet expired. This is then noted in several statistical counters

https://github.com/memcached/memcached/wiki/UserInternals#when-are-items-evicted