I've read that to improve compression, InnoDB append uncompressed data to a modification log in the compressed page (before finally recompressing).
My question is, what happens when the page needs to be flushed to disk - is the compressed page written to disk only in purely-compressed form, or with the modification log (i.e. with parts that are uncompressed)?
My question is, what happens when the page needs to be flushed to disk - is the compressed page written to disk only in purely-compressed form, or with the modification log (i.e. with parts that are uncompressed)?