What are cache eviction policies and how do they work?

What are cache eviction policies and how do they work?

Cache eviction policies determine how data is removed from a cache when it becomes full. Common policies include LRU (Least Recently Used), FIFO (First In, First Out), and LFU (Least Frequently Used). Each has its own strategy for deciding which items to evict.

Can you explain LRU in more detail?

Sure! LRU stands for Least Recently Used. It keeps track of the order in which items are accessed and evicts the least recently accessed item when space is needed. This is effective for scenarios where recently accessed data is likely to be accessed again.

What are the advantages of using FIFO?

FIFO, or First In, First Out, evicts the oldest item in the cache. Its advantage is simplicity and predictability, making it easy to implement. However, it may not always be the most efficient in terms of cache hits.

Are there any hybrid eviction policies?

Yes, hybrid policies combine elements of different strategies. For example, LRU-K keeps track of the last K accesses to an item, allowing for more nuanced eviction decisions based on access patterns.