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What are the ways to apply redis? This problem may be often seen in our daily study or work. I hope you can gain a lot from this question. The following is the reference content that the editor brings to you, let's take a look at it!

1. The operation of taking the latest N pieces of data

For example, typically fetching the latest articles from your website, we can put the ID of the latest 5000 comments in the List collection of Redis and retrieve the parts beyond the collection from the database in the following way

Use the LPUSH latest.comments command to insert data into the list collection

After inserting, use the LTRIM latest.comments 0 5000 command to save only the last 5000 ID forever.

Then we can use the following logic (pseudo code) when we get a comment on a page on the client side.

FUNCTION get_latest_comments (start,num_items): id_list = redis.lrange ("latest.comments", start,start+num_items-1) IFid_list.length < num_items id_list = SQL_DB ("SELECT... ORDER BY timeLIMIT...") END RETURN id_listEND

If you have different screening dimensions, such as the latest N items of a category, then you can create another List according to this category, and only ID, Redis is very efficient.

2. Use TOP N for ranking applications.

The difference between this requirement and the above requirements is that the previous operation takes time as the weight, and this is based on a certain condition, such as sorting by the number of times at the top, then we need our sortedset, set the value you want to sort to the score of sortedset, and set the specific data to the corresponding value. You only need to execute one ZADD command at a time.

3. Applications that need to set the expiration time accurately

For example, you can set the score value of the sorted set mentioned above to the timestamp of the expiration time, then you can simply sort the expiration time and clear the expired data regularly, not only to remove the expired data in the Redis, you can completely regard the expiration time in the Redis as an index of the data in the database, use Redis to find out which data needs to expire and delete, and then accurately delete the corresponding records from the database.

4. Counter application

Redis commands are atomic, and you can easily use INCR,DECR commands to build a counter system.

5. Uniq operation to obtain all data weight values for a certain period of time

This set data structure using Redis is the most appropriate, just keep throwing the data into the set. Set means collection, so it will be automatically weighed.

6. Real-time system, anti-garbage system

Through the set function mentioned above, you can know whether an end user has performed an operation, and you can find the collection and combination of their operations for analysis and statistical comparison. Nothing is impossible, only unexpected.

7. Pub/Sub to build a real-time message system

Redis's Pub/Sub system can build real-time messaging systems, such as many examples of real-time chat systems built with Pub/Sub.

8. Build a queue system

You can build a queue system using list, and you can even build a queue system with priority using sorted set.

9. Caching

The performance is better than Memcached, and the data structure is more diversified.

Thank you for reading! After reading the above, do you have a general understanding of the application of redis? I hope the content of the article will be helpful to all of you. If you want to know more about the relevant articles, you are welcome to follow the industry information channel.

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