InnoDB caches
Since InnoDB is the recommended engine for most use cases, configuring it is very important. The InnoDB buffer pool is a cache that should speed up most read and write operations. Thus, every DBA should know how it works. The doublewrite buffer is an important mechanism that guarantees that a row is never half-written to a file. For heavy-write workloads, we may want to disable it to obtain more speed.
InnoDB pages
Tables, data, and indexes are organized in pages, both in the caches and in the files. A page is a package of data that contains one or two rows and usually some empty space. The ratio between the used space and the total size of pages is called the fill factor.
By changing the page size, the fill factor changes inevitably. InnoDB tries to keep the pages 15/16 full. If a page's fill factor is lower than 1/2, InnoDB merges it with another page. If the rows are written sequentially, the fill factor should be about 15/16. If the rows are written randomly, the fill factor...
