Unlock 16 Powerful Redis Use Cases to Supercharge Your Applications

1. Caching

String type. For example, hot data cache (e.g., reports, trending items), object cache, full-page cache, which can improve access to hot data.

2. Distributed Data Sharing

String type, because Redis is a distributed independent service that can be shared across multiple applications, such as distributed sessions.

<dependency>
  <groupId>org.springframework.session</groupId>
  <artifactId>spring-session-data-redis</artifactId>
</dependency>

3. Distributed Lock

String type using the SETNX command; it succeeds only when the key does not exist, returning true.

public static boolean getLock(String key) {
    Long flag = jedis.setnx(key, "1");
    if (flag == 1) {
        jedis.expire(key, 10);
    }
    return flag == 1;
}

public static void releaseLock(String key) {
    jedis.del(key);
}

4. Global ID

Integer type using INCRBY, leveraging atomicity (e.g., INCRBY userid 1000) to allocate a block of IDs for sharding scenarios.

5. Counter

Integer type using INCR, suitable for page views, likes, etc., where writes go to Redis first and are later synchronized to the database.

6. Rate Limiting

Integer type using INCR with a key based on visitor IP or other attributes; each request increments the count, and exceeding the limit returns false.

7. Bitmaps (Bit Counting)

String type BITCOUNT (bitmap data structure introduced in Redis 1.6.6). Characters are stored as 8‑bit binary values, enabling space‑efficient large‑scale statistics.

SET k1 a
SETBIT k1 6 1
SETBIT k1 7 0
GET k1

/* 6 and 7 represent the modified bits of character 'a' (ASCII 97 -> 01100001) */

Examples: online user statistics, retention statistics.

SETBIT onlineusers 01
SETBIT onlineusers 11
SETBIT onlineusers 20

Bitwise operations such as AND, OR, XOR, NOT are supported.

BITOP AND destkey key1 key2 ...
BITOP OR destkey key1 key2 ...
BITOP XOR destkey key1 key2 ...
BITOP NOT destkey key

Calculate users online for seven consecutive days:

BITOP AND "7_days_both_online_users" "day_1_online_users" "day_2_online_users" ... "day_7_online_users"

8. Shopping Cart

Implemented with String or HASH. All operations possible on strings are also available on hashes.

key: user ID; field: product ID; value: quantity.

Increment: HINCRBY; decrement: custom command; delete: HDEL; retrieve all: HGETALL; count items: HLEN.

9. User Timeline

Use LIST (a doubly linked list) as a timeline; insertions keep order.

10. Message Queue

LIST

provides blocking pop operations BLPOP and BRPOP with timeout, analogous to Java's blocking queue.

Queue (FIFO): RPUSH + BLPOP.

Stack (LIFO): RPUSH + BRPOP.

11. Lottery

Use SPOP to randomly obtain a value from a set.

spop myset

12. Likes, Check‑in, Attendance

Assume a post ID t1001 and a user ID u3001. Use a set like:t1001 to store users who liked the post.

Like: SADD like:t1001 u3001 Unlike: SREM like:t1001 u3001 Check like: SISMEMBER like:t1001 u3001 All likers: SMEMBERS like:t1001 Like count:

SCARD like:t1001

13. Product Tags

Maintain all tags of a product with a set, e.g., SADD tags:i5001 "clear display".

14. Product Filtering

// Get difference
sdiff set1 set2
// Get intersection
sinter set1 set2
// Get union
sunion set1 set2

Example: an iPhone 11 product with tags brand:apple, brand:ios, screensize:6.0-6.24, screentype:lcd. Filter with:

sinter brand:apple brand:ios screensize:6.0-6.24 screentype:lcd

15. Follow / Recommendation Model

Use sets: follow for following, fans for followers.

Mutual follow: SADD 1:follow 2 and SADD 2:fans 1.

Find users I follow who also follow me (intersection):

sinter 1:follow 2:fans

Potential acquaintances (difference):

sdiff 2:follow 1:follow   // for user 1
sdiff 1:follow 2:follow   // for user 2

16. Leaderboard

Increment the score of news ID 6001:

zincrby hotNews:20190926 1 n6001

Retrieve top 15 items for today:

zrevrange hotNews:20190926 0 15 withscores