Jumpers: Why does Redis have to use jumpers to implement ordered collections?

The ordered collection of Redis is implemented by means of a hoptable, or, strictly speaking, a hash table. The core operations supported by Redis ordered collections are as follows:
- Insert data
- Delete a data
- Find a piece of data
- Find data by interval
- Iterate over an ordered sequence
- Among them, the operation of insert, delete, search and iteration output ordered sequence can also be completed by red-black tree, and the time complexity is O(logn). However, the red-black tree is not as efficient as the hop table in finding data by interval.
- For the operation of finding data by interval, the skip table can locate the beginning of the interval in order (logn) time complexity, and then iterate through the original list.
Of course, there are other reasons why Redis uses hoppers for ordered collections. For example, the code for hoppers is much easier to implement, much easier to understand and write than red-black trees, and simplicity means better readability and less error prone. Skip tables are more flexible and can balance execution efficiency and memory consumption by changing index building strategies.
However, skip tables are no substitute for red-black trees. Because red-black trees predate hops, Map types in many programming languages are implemented through red-black trees.
Skip table is a dynamic data structure, support fast read insert, delete, search operations, time complexity is O(logn)