LRU Size growth

[rohitjoshi]

I created a Lru instance with size of 1M and set 5M records. I was able to dump 4.9M+ keys using iterators.

1. Does this implementation restrict the number of elements based on the initial size?
2. Does iterator retrieve expired records as well?
3. When we iterate over all key/val, what order does it return? MRU or LRU ?

[jeromefroe]

Hmm, it sounds like there may be some bug if the size of the cache is 1M but the iterator returned 4.9M records. Would you happen to be able to share the code to reproduce the bug so I can take a look myself? In regards to your other questions:

1. Does this implementation restrict the number of elements based on the initial size?

Yes, if you specify a size for the cache in the constructor then it should never contain more than that many elements.

2. Does iterator retrieve expired records as well?

No, expired records are dropped and so they are not available to be returned by the iterator.

3. When we iterate over all key/val, what order does it return? MRU or LRU ?

The iteration is done in order from the most recently used element to the least recently used element.

[jeromefroe]

As @ssloboda noted in #29, he found and fixed a bug in pop that resulted in an item not being removed from the LRU's linked list although it was removed from the LRU's map. This would mean the item is invisible except when one gets an iterator over the LRU. It seems very likely that this is the same bug reported here. I released v0.1.13 which contains @ssloboda's fix. Since the bug description is the same, I'm going to close this issue but feel free to reopen it @rohitjoshi if you are still seeing the bug even in the new release.