Tair (Redis® OSS-Compatible):Transaction processing

Example 1: Two clients process 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 that these 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);
        // The password used to connect to the ApsaraDB for Redis instance.
        String authString = jedis.auth(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 the other 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 atomic operations:
        tx.incr(client1_key);
        tx.incr(client1_key);
        Thread.sleep(400);// The suspension of the thread does not affect the subsequent operations in the transaction. Other thread operations cannot be performed.
        tx.incr(client1_key);
        Thread.sleep(300);// The suspension of the thread does not affect the subsequent operations in the transaction. Other thread operations cannot be performed.
        tx.incr(client1_key);
        Thread.sleep(200);// The suspension of the thread does not affect the subsequent operations in the transaction. Other thread operations cannot be performed.
        tx.incr(client1_key);
        List<Object> result = tx.exec();// Execute the transaction.
        // Parse and display the results.
        for(Object rt : result){
            System.out.println("Client 1 > transaction in progress> "+rt.toString());
        }
        jedis.close();
    }
    class OtherKVStoreClient extends Thread{
        @Override
        public void run() {
            Jedis jedis = new Jedis(host, port);
            // The password used to connect to the ApsaraDB for Redis instance.
            String authString = jedis.auth(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();
        }
    }
}

After you enter the correct endpoint and password to connect to the Tair（Redis OSS-compatible） instance and run the preceding Java code, the following output is displayed. The output demonstrates that client 1 and client 2 run in two different threads. The transaction operations submitted by client 1 are executed in a sequential order. Client 2 sends requests to perform an operation on another key during this period, but the operation is blocked. Client 2 must wait until all the transaction operations of client 1 are completed.

Expected output:

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

Example 2: Two clients process the same key

The code in Example 1 is slightly modified so that two clients process the same key. The other parts of the code remain unchanged.

    ... ... 
// Note that the content of these two keys is now the same.
    static String client1_key = "KVStore-Transcation-1";
    static String client2_key = "KVStore-Transcation-1";
    ... ...

After the modified Java code is executed, the following output is displayed. The two clients run in different threads but process the same key. However, while client 1 uses the transaction mechanism to process this key, client 2 is blocked and must wait until all the transaction operations of client 1 are completed.

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