Innodb buffer pool
- Two LRU lists, New vs Old = 5:3. Both stores index and data pages
- New list is mostly explicitly hit pages by the query
- Old list is mostly read ahead pages. All pages start at the head of the old list, and will move to the new list once it is hit
- Aurora defaults to 75% of node’s physical memory
Change buffer
- Not avaiable in Aurora
- Uses buffer pool space. defaults 25% of the buffer pool, max 50%
- Cache non-clusterd index change, and merges it only when the said index page is loaded into the buffer pool
- The motivation is that modification into the secondary index is often very random access, and yet we have to read them into the buffer pool to process it