Ranking with Redis

Updated on 2023-09-28 GMT+08:00

View PDF

The best practice for DCS guides you through ranking using DCS.

Scenario

Ranking is a function commonly used on web pages and apps. It is implemented by listing key-values in descending order. However, a huge number of concurrent operation and query requests can result in a performance bottleneck, significantly increasing latency.

Ranking using DCS for Redis provides the following advantages:

Data is stored in the cache, so read/write is fast.
Multiple types of data structures, such as strings, lists, sets, and hashes are supported.

Operation Guidance

Prepare an ECS that runs the Windows OS.
Install JDK1.8 (or later) and a development tool (Eclipse is used as an example) on the ECS, and download the Jedis client.
Create a DCS instance on the DCS console. Ensure that you configure the same VPC and subnet for the DCS instance and the ECS.
Run Eclipse on the ECS and create a Java project. Then, create a productSalesRankDemo.java file for the example code, and reference the Jedis client as a library to the project.
Configure the connection address, port number, and password for the DCS instance in the example code file.
Compile and run the code.

Sample Code

package dcsDemo02;

import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import java.util.UUID;

import redis.clients.jedis.Jedis;
import redis.clients.jedis.Tuple;

public class productSalesRankDemo {
    static final int PRODUCT_KINDS = 30;

    public static void main(String[] args) {
        //Instance connection address, which is obtained from the DCS console.
        String host = "192.168.0.246";
        //Redis port number
        int port = 6379;

        Jedis jedisClient = new Jedis(host, port);

        try {
            //Instance password
            String authMsg = jedisClient.auth("******");
            if (!authMsg.equals("OK")) {
                System.out.println("AUTH FAILED: " + authMsg);
            }

            //Key
            String key = "Best-seller Rankings";

            jedisClient.del(key);

            //Generate product data at random
            List<String> productList = new ArrayList<>();
            for(int i = 0; i < PRODUCT_KINDS; i ++) {
                productList.add("product-" + UUID.randomUUID().toString());
            }

           //Generate sales volume at random
            for(int i = 0; i < productList.size(); i ++) {
                int sales = (int)(Math.random() * 20000);
                String product = productList.get(i);
               //Insert sales volume into Redis SortedSet
                jedisClient.zadd(key, sales, product);
            }

            System.out.println();
            System.out.println("                   "+key);

           //Obtain all lists and display the lists by sales volume
            Set<Tuple> sortedProductList = jedisClient.zrevrangeWithScores(key, 0, -1);
            for(Tuple product : sortedProductList) {
               System.out.println("Product ID: " + product.getElement() + ", Sales volume: "
                        + Double.valueOf(product.getScore()).intValue());
            }

            System.out.println();
            System.out.println("                   "+key);
            System.out.println("                   Top 5 Best-sellers");

            //Obtain the top 5 best-selling products and display the products by sales volume
            Set<Tuple> sortedTopList = jedisClient.zrevrangeWithScores(key, 0, 4);
            for(Tuple product : sortedTopList) {
               System.out.println("Product ID: " + product.getElement() + ", Sales volume: "
                        + Double.valueOf(product.getScore()).intValue());
            }
        }
        catch (Exception e) {
            e.printStackTrace();
        }
        finally {
            jedisClient.quit();
            jedisClient.close();
        }
    }

}

Operation Result

Compile and run the preceding Demo code. The operation result is as follows:

Best-seller Rankings
Product ID: product-b290c0d4-e919-4266-8eb5-7ab84b19862d, Sales volume: 18433
Product ID: product-e61a0642-d34f-46f4-a720-ee35940a5e7f, Sales volume: 18334
Product ID: product-ceeab7c3-69a7-4994-afc6-41b7bc463d44, Sales volume: 18196
Product ID: product-f2bdc549-8b3e-4db1-8cd4-a2ddef4f5d97, Sales volume: 17870
Product ID: product-f50ca2de-7fa4-45a3-bf32-23d34ac15a41, Sales volume: 17842
Product ID: product-d0c364e0-66ec-48a8-9ac9-4fb58adfd033, Sales volume: 17782
Product ID: product-5e406bbf-47c7-44a9-965e-e1e9b62ed1cc, Sales volume: 17093
Product ID: product-0c4d31ee-bb15-4c88-b319-a69f74e3c493, Sales volume: 16432
Product ID: product-a986e3a4-4023-4e00-8104-db97e459f958, Sales volume: 16380
Product ID: product-a3ac9738-bed2-4a9c-b96a-d8511ae7f03a, Sales volume: 15305
Product ID: product-6b8ad4b7-e134-480f-b3ae-3d35d242cb53, Sales volume: 14534
Product ID: product-26a9b41b-96b1-4de0-932b-f78d95d55b2d, Sales volume: 11417
Product ID: product-1f043255-a1f9-40a0-b48b-f40a81d07e0e, Sales volume: 10875
Product ID: product-c8fee24c-d601-4e0e-9d18-046a65e59835, Sales volume: 10521
Product ID: product-5869622b-1894-4702-b750-d76ff4b29163, Sales volume: 10271
Product ID: product-ff0317d2-d7be-4021-9d25-1f997d622768, Sales volume: 9909
Product ID: product-da254e81-6dec-4c76-928d-9a879a11ed8d, Sales volume: 9504
Product ID: product-fa976c02-b175-4e82-b53a-8c0df96fe877, Sales volume: 8630
Product ID: product-0624a180-4914-46b9-84d0-9dfbbdaa0da2, Sales volume: 8405
Product ID: product-d0079955-eaea-47b2-845f-5ff05a110a70, Sales volume: 7930
Product ID: product-a53145ef-1db9-4c4d-a029-9324e7f728fe, Sales volume: 7429
Product ID: product-9b1a1fd1-7c3b-4ae8-9fd3-ab6a0bf71cae, Sales volume: 5944
Product ID: product-cf894aee-c1cb-425e-a644-87ff06485eb7, Sales volume: 5252
Product ID: product-8bd78ba8-f2c4-4e5e-b393-60aa738eceae, Sales volume: 4903
Product ID: product-89b64402-c624-4cf1-8532-ae1b4ec4cabc, Sales volume: 4527
Product ID: product-98b85168-9226-43d9-b3cf-ef84e1c3d75f, Sales volume: 3095
Product ID: product-0dda314f-22a7-464b-ab8c-2f8f00823a39, Sales volume: 2425
Product ID: product-de7eb085-9435-4924-b6fa-9e9fe552d5a7, Sales volume: 1694
Product ID: product-9beadc07-aab0-438c-ac5e-bcc72b9d9c36, Sales volume: 1135
Product ID: product-43834316-4aca-4fb2-8d2d-c768513015c5, Sales volume: 256

            Best-seller Rankings
            Top 5 Best-sellers 
Product ID: product-b290c0d4-e919-4266-8eb5-7ab84b19862d, Sales volume: 18433
Product ID: product-e61a0642-d34f-46f4-a720-ee35940a5e7f, Sales volume: 18334
Product ID: product-ceeab7c3-69a7-4994-afc6-41b7bc463d44, Sales volume: 18196
Product ID: product-f2bdc549-8b3e-4db1-8cd4-a2ddef4f5d97, Sales volume: 17870
Product ID: product-f50ca2de-7fa4-45a3-bf32-23d34ac15a41, Sales volume: 17842

Previous topic: Serializing Access to Frequently Accessed Resources

Next topic: Implementing Bullet-Screen and Social Comments with DCS