上一篇笔记中更新了在集合中的删除，更新，查询等操作。这次尝试一下SequoiaDB的集群操作。包括复制组的创建和删除，复制组的启动和停止，在复制组中添加、删除、启动、停止节点，获取复制组中的主从节点等。 import java.util.ArrayList;import java.util.L
上一篇笔记中更新了在集合中的删除，更新，查询等操作。这次尝试一下SequoiaDB的集群操作。包括复制组的创建和删除，复制组的启动和停止，在复制组中添加、删除、启动、停止节点，获取复制组中的主从节点等。
import java.util.ArrayList;
import java.util.List;
import org.bson.BSONObject;
import org.bson.BasicBSONObject;
import com.sequoiadb.base.Node.NodeStatus;
import com.sequoiadb.base.DBCursor;
import com.sequoiadb.base.Node;
import com.sequoiadb.base.ReplicaGroup;
import com.sequoiadb.base.Sequoiadb;
import com.sequoiadb.exception.BaseException;
public class BlogRG {
static String rgName = "testRG";
static String hostName = "sdbserver1";
public static void main(String[] args) {
//连接数据库
String host = "192.168.20.46";
String port = "11810";
String usr = "admin";
String password = "admin";
Sequoiadb sdb = null;
try {
sdb = new Sequoiadb(host + ":" + port, usr, password);
} catch (BaseException e) {
e.printStackTrace();
System.exit(1);
}
//打印有关复制组信息（名称、个数）
printGroupInfo(sdb);
//清除环境，删掉重复的复制组
if(isGroupExist(sdb,rgName)){
System.out.println("Removing the old replica group...");
sdb.removeReplicaGroup(rgName);
}
printGroupInfo(sdb);
//添加新复制组
System.out.println("Adding the new replica group...");
ReplicaGroup rg = sdb.createReplicaGroup(rgName);
printGroupInfo(sdb);
//打印复制组内节点信息
System.out.println("Tere are " + rg.getNodeNum(NodeStatus.SDB_NODE_ALL) + " nodes in the group.");
//添加三个新的节点
Node node1 = addNode(rg,50000);
Node node2 = addNode(rg,50010);
Node node3 = addNode(rg,50020);
//打印复制组内节点信息
System.out.println("Tere are " + rg.getNodeNum(NodeStatus.SDB_NODE_ALL) + " nodes in the group.");
//获取复制组的主从节点
Node master = rg.getMaster();
System.out.println("The master node is " +master.getPort());
System.out.println("The slave node is " + rg.getSlave().getPort());
//停止主节点
System.out.println("stoping the master node...");
master.stop();
//等待主节点停止
while(rg.getMaster().getPort() == master.getPort()){
try{
Thread.sleep(2000);
} catch (Exception e){
}
}
//查看新选举的主节点
System.out.println("re-selecting the master node...");
System.out.println("The master node is " + rg.getMaster().getPort());
}
private static void printGroupInfo(Sequoiadb sdb){
ArrayList names = sdb.getReplicaGroupNames();
int count = 0;
System.out.print("The replica groups are ");
for (Object name : names){
count++;
System.out.print((String)name + ", ");
}
System.out.println("\nThere are " + count + " replica groups in total.");
}
private static boolean isGroupExist(Sequoiadb sdb, String rgName){
ArrayList names = sdb.getReplicaGroupNames();
for (Object name : names){
if(rgName.equals((String)name))
return true;
}
return false;
}
private static Node addNode(ReplicaGroup rg, int port){
if(rg.getNode(hostName,port)!= null)
rg.removeNode(hostName, port, null);
Node node = rg.createNode(hostName,port,"/opt/sequoiadb/database/test/" + port,null);
System.out.println("starting the node " + port + "...");
node.start();
return node;
}
}
上面的代码在数据库中添加新的复制组，并在新的复制组内添加三个主节点，数据组自动选举出新的主节点，停止主节点后，复制组内重新选举新的主节点。
运行以上代码后的结果是：
The replica groups are SYSCatalogGroup, datagroup, testRG, There are 3 replica groups in total. Removing the old replica group... The replica groups are SYSCatalogGroup, datagroup, There are 2 replica groups in total. Adding the new replica group... The replica groups are SYSCatalogGroup, datagroup, testRG, There are 3 replica groups in total. Tere are 0 nodes in the group. starting the node 50000... starting the node 50010... starting the node 50020... Tere are 3 nodes in the group. The master node is 50000 The slave node is 50010 stoping the master node... re-selecting the master node... The master node is 50020
运行完成后，通过shell控制台查看数据库testRG复制组的详细情况：
>rg.getDetail()
{
"Group": [
{
"HostName": "sdbserver1",
"dbpath": "/opt/sequoiadb/database/test/50000",
"Service": [
{
"Type": 0,
"Name": "50000"
},
{
"Type": 1,
"Name": "50001"
},
{
"Type": 2,
"Name": "50002"
}
],
"NodeID": 1053
},
{
"HostName": "sdbserver1",
"dbpath": "/opt/sequoiadb/database/test/50010",
"Service": [
{
"Type": 0,
"Name": "50010"
},
{
"Type": 1,
"Name": "50011"
},
{
"Type": 2,
"Name": "50012"
}
],
"NodeID": 1054
},
{
"HostName": "sdbserver1",
"dbpath": "/opt/sequoiadb/database/test/50020",
"Service": [
{
"Type": 0,
"Name": "50020"
},
{
"Type": 1,
"Name": "50021"
},
{
"Type": 2,
"Name": "50022"
}
],
"NodeID": 1055
}
],
"GroupID": 1023,
"GroupName": "testRG",
"PrimaryNode": 1055,
"Role": 0,
"Status": 0,
"Version": 4,
"_id": {
"$oid": "53d9d38e14a63a88c621edd8"
}
}
Return 1 row(s).
Takes 0.4716s.
