Process transactions

Example 1: Two clients operate on different keys

Sample code:

package transcation.kvstore.aliyun.com;
import java.util.List;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.Transaction;

public class KVStoreTranscationTest {
    static final String host = "xxxxxx.m.cnhza.kvstore.aliyuncs.com";
    static final int port = 6379;
    static final String password = "password";
    //  Note: The two keys have different content.
    static String client1_key = "KVStore-Transcation-1";
    static String client2_key = "KVStore-Transcation-2";
    public static void main(String[] args) {
        Jedis jedis = new Jedis(host, port);
        String authString = jedis.auth(password);  // Instance password (password)
        if (!authString.equals("OK")) {
            System.err.println("Authentication failed: " + authString);
            jedis.close();
            return;
        }
        jedis.set(client1_key, "0");
        // Start another thread to simulate another client.
        new KVStoreTranscationTest().new OtherKVStoreClient().start();
        Thread.sleep(500);
        Transaction tx = jedis.multi();// Start the transaction.
        // The following operations are submitted to the server as an atomic operation.
        tx.incr(client1_key);
        tx.incr(client1_key);
        Thread.sleep(400);// Pausing this thread does not affect consecutive operations in the transaction. Other threads cannot execute operations either.
        tx.incr(client1_key);
        Thread.sleep(300);// Pausing this thread does not affect consecutive operations in the transaction. Other threads cannot execute operations either.
        tx.incr(client1_key);
        Thread.sleep(200);// Pausing this thread does not affect consecutive operations in the transaction. Other threads cannot execute operations either.
        tx.incr(client1_key);
        List<Object> result = tx.exec();// Execute the transaction.
        // Parse and print the results.
        for(Object rt : result){
            System.out.println("Client 1 > In transaction > "+rt.toString());
        }
        jedis.close();
    }
    class OtherKVStoreClient extends Thread{
        @Override
        public void run() {
            Jedis jedis = new Jedis(host, port);
            String authString = jedis.auth(password);// Instance password (password)
            if (!authString.equals("OK")) {
                System.err.println("AUTH Failed: " + authString);
                jedis.close();
                return;
            }
            jedis.set(client2_key, "100");
            for (int i = 0; i < 10; i++) {
                try {
                    Thread.sleep(300);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println("Client 2 > "+jedis.incr(client2_key));
            }
            jedis.close();
        }
    }
}

Run the program with the correct endpoint and password for your Tair (Redis OSS-compatible) instance. In the output, client1's transaction operations execute as an atomic block. Client2 is blocked until the transaction completes, even though it uses a different key.

Expected output:

Client 2 > 101
Client 2 > 102
Client 2 > 103
Client 2 > 104
Client 1 > In transaction > 1
Client 1 > In transaction > 2
Client 1 > In transaction > 3
Client 1 > In transaction > 4
Client 1 > In transaction > 5
Client 2 > 105
Client 2 > 106
Client 2 > 107
Client 2 > 108
Client 2 > 109
Client 2 > 110

Example 2: Two clients operate on the same key

This example modifies Example 1 so both clients operate on the same key. The rest of the code is unchanged.

    ... ... 
//  Note: The two keys now have the same content.
    static String client1_key = "KVStore-Transcation-1";
    static String client2_key = "KVStore-Transcation-1";
    ... ...

Run the modified program. When client1 uses a transaction on the shared key, client2 is blocked until the transaction completes.

Client 2 > 101
Client 2 > 102
Client 2 > 103
Client 2 > 104
Client 1 > In transaction > 105
Client 1 > In transaction > 106
Client 1 > In transaction > 107
Client 1 > In transaction > 108
Client 1 > In transaction > 109
Client 2 > 110
Client 2 > 111
Client 2 > 112
Client 2 > 113
Client 2 > 114
Client 2 > 115