What is a Cache Algorithm?
Q: What is a Cache Algorithm?
A: A Cache algorithm is an algorithm used to manage a cache or group of data. It decides which item should be deleted from the cache when it is full.
Q: What is hit rate?
A: Hit rate describes how often a request can be served from the cache.
Q: What does latency describe?
A: Latency describes for how long a cached item can be obtained.
Q: What is Belady's optimal algorithm?
A: Belady's optimal algorithm, also known as the clairvoyant algorithm, is an efficient caching algorithm that always discards the information that will not be needed for the longest time in the future. This result cannot generally be implemented in practice because it requires predicting what will be needed far into the future.
Q: How does Least Recently Used (LRU) work?
A: LRU deletes the least recently used items first and requires keeping track of what was used when by using "age bits" for each cache-line and tracking which one was least recently used based on age-bits. Every time a cache-line is used, all other cache-lines' ages are changed accordingly.
Q: How does Most Recently Used (MRU) work?
A: MRU deletes the most recently used items first and this caching mechanism is commonly used for database memory caches.
Q: What other algorithms exist to maintain cache coherency?
A; Various algorithms exist to maintain cache coherency when multiple independent caches are being used for shared data, such as multiple database servers updating a single shared data file.
