What are the differences between LFU and LRU caching algorithms?

What are the differences between LFU and LRU caching algorithms?

LFU (Least Frequently Used) and LRU (Least Recently Used) are both caching algorithms, but they prioritize different aspects. LFU evicts the least frequently accessed items, while LRU evicts the least recently accessed items.

Can you explain how LFU keeps track of usage?

LFU maintains a count of how many times each item is accessed. When an item is accessed, its count is incremented. The item with the lowest count is evicted when space is needed.

What about LRU? How does it track access?

LRU uses a data structure, often a linked list, to keep track of the order of access. When an item is accessed, it is moved to the front of the list, and the least recently used item at the back is evicted when necessary.

Which algorithm is better for a web application?

It depends on the use case. LRU is often better for applications with temporal locality, while LFU can be more effective when certain items are consistently accessed more frequently.