memcached java下性能测试报告、分析与问题讨论

程序员文章站 2024-01-10 14:16:13

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我的项目原来使用静态HashMap来实现Key->Object的缓存,并且实现脏数据刷新.由于项目要改成集群部署.在单个jvm里运行的静态Hash结构已经无法处理脏数据问题.所以准备使用memcached做分布式缓存来解决.

从网上搜索到的资料来看 memcached能够接受较大量的请求.但其javaclient 由于大量使用同步语句、hashmap，读取流没有使用bufferedStream。造成性能并不好
为此在我的项目里我参考memcached的协议，自己实现一个客户端功能。经过测试后发现一些问题。

测试环境1：
windows xp home
迅驰T2250
1G内存
jdk1.5
server: memcached-1.2.1 nt版本
client: 自己编写
用于传输的pojo 40个属性，序列化后为750个byte
测试client与server同台机器

测试方法
填充测试时填充10w个pojo。创建100个任务，每任务负责向memcached存储1000个pojo。
读取测试时读取10000个pojo 创建100个任务，每任务读取100个pojo。
平均值均按照线程内取平均值后，各线程再取平均值。
在进行上述测试的时候 cpu占用均在90%－100%，根据上述测试结果，开2个线程时效率最高。

thread count	write avg/per obj	write totall	read avg/per obj	read total
10	2.404991 ms	29s	1.709544 ms	2s
5	0.704780 ms	18s	1.333013 ms	2s
2	0.262194 ms	15s	0.414683 ms	2s

测试环境2:
AIX5.2
IBM P650 Power4 1.5G(64bit) *4
内存8G
jdk1.4
memcached-1.2.1
libevnet1.1b
client自己编写
用于传输的pojo 40个属性，序列化后为750个byte
测试client与server同台机器

相同的测试方法。测试结果大跌眼睛 10线程时读写速度为200ms/per object 比我的笔记本慢100倍。就没继续测试

测试环境3：
windows2000 server
xeon 1.5*4
内存8G
jdk1.5
测试时发现cpu占用不高于20%

thread count	write avg/per obj	write total	read avg/per obj	read total
20	10.266615ns	71s	23.21283ns	15s
10	4.341574ns	41s	13.30084ns	16s
5	1.298717ns	25s	9.33258ns	18s
2	1.298717ns	21s	4.02503ns	23s

初步测试到这里发现的问题
1.是暂时没有达到网上宣传的1.5w个对象/s (目前测试cpu为瓶颈)
2.是aix下效率低的可怕，对aix不太熟悉。应该有些设置的参数，这点还要向大家请教。
3.超过2个线程效率就开始低。没有发挥多线程的优势，不知道大家在使用过程中有没有发现这一点，还是说我写的MemBufferedDriver有问题。

我的期望是读写速度均能稳定在0.1毫秒左右，至少 1w obj/s 这样才有可能不影响到现有系统的效率
另外大家在java下使用memcached的时候效率怎么样都是怎么用的呢

下面贴下我的client的实现
memcached的协议可以参考memcache包的doc/protocol.txt

主要是socket初次打开后不关闭，直接存放到ThreadLocal中，与memcached保持一个长练接。每次使用的时候判断连接可用还是需要重新连接。

其他存储和读取实现memcached协议。使用BufferedStream。
序列化采用实现Serializable，直接使用ObjectStream来实现。(由于都是pojo简单数据对象，尝试过实现Externalizable接口自己实现序列化和使用750个byte的String 来序列化，发现性能相差不多故放弃)

java 代码
MemBufferedDriver 为client实现

public class MemBufferedDriver {
/**
* 存放连到cacheserver的socket连接
*/
private final static ThreadLocal sockPool = new ThreadLocal();
private static String serverAddress = "localhost:11211";
public static final byte[] BYTE_GET = new byte[]{103, 101, 116, 32};
public static final byte[] BYTE_SET = new byte[]{115, 101, 116, 32};
public static final byte[] BYTE_DELETE = new byte[]{100, 101, 108, 101, 116, 101, 32};
public static final byte[] BYTE_CRLF = new byte[]{13, 10};
public static final byte[] BYTE_SPACE = new byte[]{32};
public static final String SERVER_STATUS_DELETED = "DELETED";
public static final String SERVER_STATUS_NOT_FOUND = "NOT_FOUND";
public static final String SERVER_STATUS_STORED = "STORED";
public static final String SERVER_STATUS_ERROR = "ERROR";
public static final String SERVER_STATUS_END = "END";
public static final String SERVER_STATUS_VALUE = "VALUE";
public static final String ENCODING_TYPE = "UTF-8";
public static Socket getSocket() throws UnknownHostException, IOException {
Socket s = (Socket) MemBufferedDriver.sockPool.get();
if (s == null || s.isClosed()) {
s = MemBufferedDriver.reconnect();
MemBufferedDriver.sockPool.set(s);
}
return s;
}
private static Socket reconnect() throws UnknownHostException, IOException {
String[] ip = MemBufferedDriver.serverAddress.split(":");
return new Socket(ip[0], Integer.parseInt(ip[1]));
}
public Map getMulti(String[] keys) {
Map map = new HashMap();
if (keys == null || keys.length <= 0) return map;
for (int i = 0; i < keys.length; i++) {
Object o = get(keys[i]);
if (o != null) map.put(keys[i], o);
}
return map;
}
public Object[] getMultiArray(String[] keys) {
if (keys == null || keys.length <= 0) return null;
Object[] o = new Object[keys.length];
for (int i = 0; i < keys.length; i++)
o[i] = get(keys[i]);
return o;
}
public boolean set(String key, Object obj) {
try {
if (obj == null || key == null || "".equals(key)) throw new Exception("对象和key 不能为空");
Socket s = MemBufferedDriver.getSocket();
BufferedInputStream in = new BufferedInputStream(s.getInputStream());
BufferedOutputStream out = new BufferedOutputStream(s.getOutputStream());
key = encodeKey(key);
int flag = 0;
//序列化对象
byte[] bs = object2Byte(obj);
out.write(MemBufferedDriver.BYTE_SET); //write cmd
out.write(key.getBytes()); //write key
out.write(MemBufferedDriver.BYTE_SPACE);
out.write(String.valueOf(flag).getBytes()); //write flag
out.write(MemBufferedDriver.BYTE_SPACE);
out.write("0".getBytes()); //write expire date
out.write(MemBufferedDriver.BYTE_SPACE);
out.write(String.valueOf(bs.length).getBytes()); //object length
out.write(MemBufferedDriver.BYTE_CRLF);
out.write(bs);
out.write(MemBufferedDriver.BYTE_CRLF);
out.flush();
String ret = readLine(in);
return MemBufferedDriver.SERVER_STATUS_STORED.equals(ret);
} catch (Exception e) {
System.out.println(e.getMessage());
return false;
}
}
public Object get(String key) {
try {
Socket s = MemBufferedDriver.getSocket();
InputStream in = s.getInputStream();
OutputStream out = s.getOutputStream();
key = encodeKey(key);
out.write(MemBufferedDriver.BYTE_GET);
out.write(key.getBytes());
out.write(MemBufferedDriver.BYTE_CRLF);
out.flush();
return getObjectFromStream(in, out);
} catch (Exception e) {
System.out.println(e.getMessage());
return null;
}
}
public boolean delete(String key) {
try {
Socket s = MemBufferedDriver.getSocket();
InputStream in = s.getInputStream();
OutputStream out = s.getOutputStream();
key = encodeKey(key);
out.write(MemBufferedDriver.BYTE_DELETE);
out.write(key.getBytes());
out.write(MemBufferedDriver.BYTE_CRLF);
out.flush();
String ret = readLine(in);
return MemBufferedDriver.SERVER_STATUS_DELETED.equals(ret) || MemBufferedDriver.SERVER_STATUS_NOT_FOUND.equals(ret);
} catch (Exception e) {
return false;
}
}
private Object getObjectFromStream(InputStream in, OutputStream out) throws IOException, ClassNotFoundException {
String cmd = readLine(in);
if (cmd.startsWith(MemBufferedDriver.SERVER_STATUS_VALUE)) {
//return object
String[] part = cmd.split(" ");
String para = part[2];
int length = Integer.parseInt(part[3]);
byte[] bs = new byte[length];
int count = 0;
while (count < bs.length) count += in.read(bs, count, (bs.length - count));
if (count != bs.length)
throw new IOException("读取数据长度错误");
readLine(in);
String endstr = readLine(in);
if (MemBufferedDriver.SERVER_STATUS_END.equals(endstr))
return this.byte2Object(bs);
else
System.out.println("结束标记错误");
}
return null;
}
private String encodeKey(String key) throws UnsupportedEncodingException {
return URLEncoder.encode(key, MemBufferedDriver.ENCODING_TYPE);
}
private String readLine(InputStream in) throws IOException {
ByteArrayOutputStream bos = new ByteArrayOutputStream();
boolean eol = false;
byte[] b = new byte[1];
while (in.read(b, 0, 1) != -1) {
if (b[0] == 13) eol = true;
else if (eol && b[0] == 10) break;
else
eol = false;
bos.write(b, 0, 1);
}
if (bos.size() == 0) return null;
return bos.toString().trim();
}
private byte[] object2Byte(Object o) throws IOException {
ByteArrayOutputStream b = new ByteArrayOutputStream();
new ObjectOutputStream(b).writeObject(o);
return b.toByteArray();
}
private Object byte2Object(byte[] b) throws IOException, ClassNotFoundException {
return new ObjectInputStream(new ByteArrayInputStream(b)).readObject();
}
public static void main(String[] args) throws Exception {
MemBufferedDriver m = new MemBufferedDriver();
System.out.println(m.set("a", "DsSD"));
System.out.println(m.get("a"));
}
public static void setServerAddress(String serverAddress) {
MemBufferedDriver.serverAddress = serverAddress;
}
}

java 代码
写入测试类

public class Fill2Server extends Thread {
public static int THREAD_COUNT = 2;
public static Queue queue = new Queue();
MemBufferedDriver md = new MemBufferedDriver();
public static void main(String[] args) throws Exception {
int size ;
if (args.length == 3 && args[0] != null && args[1] != null) {
MemDriver.setServerAddress(args[0]);
size = Integer.parseInt(args[1]);
THREAD_COUNT = Integer.parseInt(args[2]);
new Fill2Server().doFill(size);
} else
System.out.println("参数1 连接服务器地址 ipaddress:port ,参数2填充数量,不能小于10000,参数3为使用的线程数");
}
private void doFill(int size) throws InterruptedException {
int taskCount = size / 1000; //每个线程负责填充1000的对象
for (int i = 0; i < taskCount; i++) {
Task t = new Task();
t.setTaskId(String.valueOf(i));
queue.add(t);
}
long time = System.currentTimeMillis();
Thread tr[] = new Thread[THREAD_COUNT];
for (int i = 0; i < THREAD_COUNT; i++) {
FillThread ft = new FillThread();
(tr[i] = new Thread(ft)).start();
}
//监控填充完成
while (true) {
boolean flag = true;
for (int i = 0; i < THREAD_COUNT; i++)
flag &= tr[i].isAlive();
if (!flag) break;
Thread.sleep(1000);
}
time = System.currentTimeMillis() - time;
System.out.println("任务完成,共用" + (time / 1000) + "s");
}
class FillThread implements Runnable {
public void run() {
Task task;
while (true) {
task = (Task) queue.get();
if (task == null) break;
long time = System.nanoTime();
for (int i = 0; i < 1000; i++) {
TestBO b = new TestBO();
md.set(task.getTaskId() + i, b);
}
time = System.nanoTime() - time;
System.out.println(Thread.currentThread().getName() + " avg " + (time / 1000) + " ns ");
}
}
}
}

java 代码
读取的测试方法

public class GetFromServer extends Thread {
public static int THREAD_COUNT = 2;
public static Queue queue = new Queue();
MemDriver md = new MemDriver();
public static void main(String[] args) throws Exception {
int size;
if (args.length == 3 && args[0] != null && args[1] != null) {
MemDriver.setServerAddress(args[0]);
size = Integer.parseInt(args[1]);
THREAD_COUNT = Integer.parseInt(args[2]);
new GetFromServer().doFill(size);
} else
System.out.println("参数1 连接服务器地址 ipaddress:port ,参数2读取数量不能小于1000,参数3为使用的线程数");
}
private void doFill(int size) throws InterruptedException {
int taskCount = size / 100; //每个线程负责填充1000的对象
for (int i = 0; i < taskCount; i++) {
Task t = new Task();
t.setTaskId(String.valueOf(i));
GetFromServer.queue.add(t);
}
long time = System.currentTimeMillis();
Thread tr[] = new Thread[GetFromServer.THREAD_COUNT];
for (int i = 0; i < GetFromServer.THREAD_COUNT; i++) {
GetFromServer.FillThread ft = new GetFromServer.FillThread();
(tr[i] = new Thread(ft)).start();
}
//监控填充完成
while (true) {
boolean flag = true;
for (int i = 0; i < GetFromServer.THREAD_COUNT; i++)
flag &= tr[i].isAlive();
if (!flag) break;
Thread.sleep(1000);
}
time = System.currentTimeMillis() - time;
System.out.println("任务完成,共用" + (time / 1000) + "s");
}
class FillThread implements

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