Bottom: Quick List quicklist
In earlier versions redis in, list the bottom using ziplist and linkedlist (elements came ziplist, long linkedlist), and later because the space occupied by a large list pointer replaced now quicklist, quicklist is a mixture of the two, it will linkedlist press split segments, each segment is a ziplist, each connected by a bidirectional pointer ziplist. ziplist 8k byte memory a default, this configuration can be adjusted.
Compression depth
redis ziplist will be compressed in order to support the rapid push and pop, head and tail are generally two ziplist not compressed, that is, compression depth of 1, the default depth is 0, the configuration can also be adjusted.