A brief understanding of cache and buffer

A brief understanding of the two concepts of cache and buffer during Oracle and MySQL learning. I checked these concepts and found them easy to understand and record here for the sake of forgetting (I) cache, is a method used to accelerate reading. The objective is to accelerate the reading of physical cache, including cpu-managed L1 cache, L2 cache, and memory cache access to the cache, which can be divided into cache hit or cache miss. Generally, the larger the cache, the higher the cache hit rate, the faster the access speed. Visitors do not know that the data must be in the cache (ii) buffer, which only refers to the memory region. The software is used to save specific information. The Buffer is allocated on demand. It is enough to save the data. The software has an appropriate mechanism to know that the data is in the buffer.