I. AeroSpike configuration

1. Configuration file location: / etc/aerospike/aerospike.conf

2. Notes:
    <1> The bin key name limits the number of bytes to no more than 14 bytes
    <2> Each node in the cluster has a configuration file aerospike.conf, and the namespace configuration parameters in each node configuration file must be consistent
    < 3 > replication factor is a configuration parameter that cannot exceed the number of cluster nodes. The more copies, the higher the reliability, but the higher the write request that must go through all the data copies. In practice, most deployments use a data factor of 2 (one master data and one copy)

Configuration of aerospike.conf:

# Aerospike database configuration file for use with systemd.
service {
        paxos-single-replica-limit 1 # Number of nodes where the replica count is automatically reduced to 1.
        service-threads 4
        transaction-queues 4
        transaction-threads-per-queue 4
        proto-fd-max 15000
}
logging {
        file /var/log/aerospike/aerospike.log {
                context any info
        }
}
network {
        service {
                address any
                port 3000
        }
        heartbeat {
                mode multicast
                multicast-group 239.1.99.222
                port 9918
                # To use unicast-mesh heartbeats, remove the 3 lines above, and see
                # aerospike_mesh.conf for alternative.
                interval 150
                timeout 10
        }
        fabric {
                port 3001
        }
        info {
                port 3003
        }
}

namespace test {
        replication-factor 2
        memory-size 4G
        default-ttl 30d # 30 days, use 0 to never expire/evict.
        storage-engine memory
}
namespace default {
        replication-factor 2
        memory-size 4G
        default-ttl 30d # 30 days, use 0 to never expire/evict.
        storage-engine memory
        # To use file storage backing, comment out the line above and use the
        # following lines instead.
#       storage-engine device {
#               file /opt/aerospike/data/bar.dat
#               filesize 16G
#               data-in-memory true # Store data in memory in addition to file.
#       }
}

Java Client Operation

1. Connect to AeroSpike Cluster

(1) Cluster discovery by connecting a node

AerospikeClient client = new AerospikeClient("127.0.0.1", 3000);

(2) Cluster discovery by configuring multiple nodes

Host[] hosts = new Host[] {
    new Host("a.host", 3000),
    new Host("another.host", 3000),
    new Host("and.another.host", 3000)
};
AerospikeClient client = new AerospikeClient(new ClientPolicy(), hosts);

• The advantage of the second connection over the first one is that the host configuration is read sequentially by the second connection until it is connected to the cluster and stopped reading. In the first connection, if the host is unresponsive, it will not be able to connect to the cluster.

(3) Connections with privileged authentication

import com.aerospike.client.AerospikeClient;
import com.aerospike.client.Host;
import com.aerospike.client.policy.ClientPolicy;
Host[] hosts = new Host[] {
    new Host("a.host", 3000),
    new Host("another.host", 3000),
    new Host("and.another.host", 3000)
};
ClientPolicy policy = new ClientPolicy();
policy.user = "myuser";
policy.password = "mypass";
AerospikeClient client = new AerospikeClient(policy, hosts);

2. Writing Records

// Initialize policy.
WritePolicy policy = new WritePolicy();
policy.timeout = 50;  // 50 millisecond timeout.

Single Value Writing

// Write single value.
Key key = new Key("test", "myset", "mykey");
Bin bin = new Bin("mybin", "myvalue");
client.put(policy, key, bin);

Multivalue Writing

// Write multiple values.
Key key = new Key("test", "myset", "mykey");
Bin bin1 = new Bin("name", "John");
Bin bin2 = new Bin("age", 25);
client.put(policy, key, bin1, bin2);

Delete values (using asNull)

Key key = new Key("test", "myset", "mykey");
Bin bin1 = Bin.asNull(binName1); // Set bin value to null to drop bin.
client.put(policy, key, bin1);

3. Reading Records

Read all field information for the specified Key

Record record = client.get(policy, key);

Read specific field information for the specified Key

Record record = client.get(policy, key, "name", "age");

4. Delete records

Key key = new Key("test", "myset", "mykey");
client.delete(policy, key);

5. Batch reading of multiple Key records

Key[] keys = new Key[size];
for (int i = 0; i < size; i++) {
    keys[i] = new Key("test", "myset", (i + 1));
}
Record[] records = client.get(policy, keys);

6. Scanning records, i.e. acquiring all records

public final class ScanParallelTest implements ScanCallback {
    public static void main(String[] args) {
        try {
            new ScanParallelTest().runTest();
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }
    private int recordCount;
    public void runTest() throws AerospikeException {
        AerospikeClient client = new AerospikeClient("127.0.0.1", 3000);
        try {
            ScanPolicy policy = new ScanPolicy();
            policy.concurrentNodes = true;
            policy.priority = Priority.LOW;
            policy.includeBinData = false;
            client.scanAll(policy, "test", "demoset", this);       
            System.out.println("Records " + recordCount);
        }
        finally {
            client.close();
        }
    }
    public void scanCallback(Key key, Record record) {
        recordCount++;
        if ((recordCount % 10000) == 0) {
            System.out.println("Records " + recordCount);
        }
    }
}