33 - Introduction à Go: Redis & Ordered Sets - part 1 [Niveau moyen]

Опубликовано: 28 Март 2020
на канале: Hassane Moustapha

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Go: Redis & Ordered Sets - part 1 [Niveau moyen]

Sorted sets
Redis Sorted Sets are, similarly to Redis Sets, non repeating collections of Strings. The difference is that every member of a Sorted Set is associated with score, that is used in order to take the sorted set ordered, from the smallest to the greatest score. While members are unique, scores may be repeated.

With sorted sets you can add, remove, or update elements in a very fast way (in a time proportional to the logarithm of the number of elements). Since elements are taken in order and not ordered afterwards, you can also get ranges by score or by rank (position) in a very fast way. Accessing the middle of a sorted set is also very fast, so you can use Sorted Sets as a smart list of non repeating elements where you can quickly access everything you need: elements in order, fast existence test, fast access to elements in the middle!

In short with sorted sets you can do a lot of tasks with great performance that are really hard to model in other kind of databases.

With Sorted Sets you can:

Take a leaderboard in a massive online game, where every time a new score is submitted you update it using ZADD. You can easily take the top users using ZRANGE, you can also, given a user name, return its rank in the listing using ZRANK. Using ZRANK and ZRANGE together you can show users with a score similar to a given user. All very quickly.
Sorted Sets are often used in order to index data that is stored inside Redis. For instance if you have many hashes representing users, you can use a sorted set with elements having the age of the user as the score and the ID of the user as the value. So using ZRANGEBYSCORE it will be trivial and fast to retrieve all the users with a given interval of ages.
Sorted Sets are probably the most advanced Redis data types, so take some time to check the full list of Sorted Set commands to discover what you can do with Redis! Also you may want to read the introduction to Redis data types.

#redis #go #golang #sets #data #structure

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