本文已参与「新人创作礼」活动，一起开启掘金创作之路。
事前准备
先往数据库中添加 1w 条数据
简单循环事务提交
/**
* 循环操作，自动事务提交
* 耗时 1066816 ms
*/
@Test
public void testUpdateV1() {
List<MybatisTest> list = mapper.selectList(new QueryWrapper<>());
long start = System.currentTimeMillis();
for (MybatisTest test : list) {
test.setTestStr("test_str1");
mapper.updateById(test);
}
long end = System.currentTimeMillis();
System.out.println("总计耗时:" + (end - start));
}
感觉耗时有点高，不知道是什么原因导致的
手动事务提交
/**
* 循环操作，手动事务提交
* 耗时 37869 ms
*/
@Test
public void testUpdateV2() {
List<MybatisTest> list = mapper.selectList(new QueryWrapper<>());
long start = System.currentTimeMillis();
TransactionStatus transactionStatus = dataSourceTransactionManager.getTransaction(transactionDefinition);
try {
for (MybatisTest test : list) {
test.setTestStr("test_str2");
mapper.updateById(test);
}
dataSourceTransactionManager.commit(transactionStatus);
} catch (Exception e) {
dataSourceTransactionManager.rollback(transactionStatus);
} finally {
long end = System.currentTimeMillis();
System.out.println("总计耗时:" + (end - start));
}
}
不是每次更新都提交一次事务，所以效率会提高
批量提交
/**
* 批量更新
* 耗时: 5480 ms
*/
@Test
public void testUpdateV4() {
List<MybatisTest> list = mapper.selectList(new QueryWrapper<>());
List<MybatisTest> result = new ArrayList<>();
long start = System.currentTimeMillis();
for (MybatisTest mybatisTest : list) {
mybatisTest.setTestStr("test_str1");
result.add(mybatisTest);
}
mapper.updateBatchById(result);
long end = System.currentTimeMillis();
System.out.println("总耗时:" + (end - start));
}
多线程事务提交
/**
* 多线程操作，手动事务提交
* 子线程：pool-1-thread-1耗时:9875 ms
* 子线程：pool-1-thread-4耗时:9910 ms
* 子线程：pool-1-thread-3耗时:10055 ms
* 子线程：pool-1-thread-5耗时:10054 ms
* 子线程：pool-1-thread-2耗时:10325 ms
*/
@Test
public void testUpdateV3() {
List<MybatisTest> list = mapper.selectList(new QueryWrapper<>());
// 线程数量
final int threadCount = 5;
// 每个线程处理的数据量
final int dataPartionLength = (list.size() + threadCount - 1) / threadCount;
// 创建多线程处理任务
ExecutorService studentThreadPool = Executors.newFixedThreadPool(threadCount);
CountDownLatch countDownLatch = new CountDownLatch(threadCount);
for (int i = 0; i < threadCount; i++) {
// 每个线程处理的数据
List<MybatisTest> tmp = list.stream()
.skip((long) i * dataPartionLength).limit(dataPartionLength).collect(Collectors.toList());
studentThreadPool.execute(() -> {
testUpdate(tmp, countDownLatch);
});
}
try {
// 倒计时锁设置超时时间 30s
countDownLatch.await(30, TimeUnit.SECONDS);
} catch (Throwable e) {
e.printStackTrace();
}
System.out.println("主线程完成");
}
private void testUpdate(List<MybatisTest> list, CountDownLatch countDownLatch) {
TransactionStatus transactionStatus = dataSourceTransactionManager.getTransaction(transactionDefinition);
long start = System.currentTimeMillis();
try {
list.forEach(s -> {
s.setTestStr("test_str3");
mapper.updateById(s);
});
dataSourceTransactionManager.commit(transactionStatus);
countDownLatch.countDown();
} catch (Throwable e) {
e.printStackTrace();
dataSourceTransactionManager.rollback(transactionStatus);
} finally {
long end = System.currentTimeMillis();
System.out.println("子线程：" + Thread.currentThread().getName() + "耗时:" + (end - start));
}
}
基于 CountDownLatch 控制多线程事务提交
/**
* 多线程操作，手动控制事务
* 子线程提交：pool-1-thread-1耗时:8240 ms
* 子线程提交：pool-1-thread-3耗时:8295 ms
* 子线程提交：pool-1-thread-2耗时:8334 ms
* 子线程提交：pool-1-thread-5耗时:8122 ms
* 子线程提交：pool-1-thread-4耗时:8181 ms
*/
@Test
public void testUpdateV5() {
List<MybatisTest> list = mapper.selectList(new QueryWrapper<>());
// 线程数量
final int threadCount = 5;
// 每个线程处理的数据量
final int dataPartionLength = (list.size() + threadCount - 1) / threadCount;
// 创建多线程处理任务
ExecutorService studentThreadPool = Executors.newFixedThreadPool(threadCount);
// 用于计算子线程提交数量
CountDownLatch countDownLatch = new CountDownLatch(threadCount);
// 用于判断主线程是否提交
CountDownLatch mainLatch = new CountDownLatch(1);
// 用于判断子线程任务是否有错误
AtomicBoolean flag = new AtomicBoolean();
for (int i = 0; i < threadCount; i++) {
// 每个线程处理的数据
List<MybatisTest> tmp = list.stream()
.skip((long) i * dataPartionLength).limit(dataPartionLength).collect(Collectors.toList());
studentThreadPool.execute(() -> {
testUpdate(tmp, countDownLatch, mainLatch, flag);
});
}
try {
// 倒计时锁设置超时时间 30s
boolean await = countDownLatch.await(30, TimeUnit.SECONDS);
if (!await) {
System.out.println("执行超时!");
flag.set(true);
}
} catch (Throwable e) {
e.printStackTrace();
flag.set(true);
}
mainLatch.countDown();
studentThreadPool.shutdown();
System.out.println("主线程完成");
System.out.println(flag);
}
private void testUpdate(List<MybatisTest> list, CountDownLatch countDownLatch, CountDownLatch mainLatch, AtomicBoolean flag) {
TransactionStatus transactionStatus = dataSourceTransactionManager.getTransaction(transactionDefinition);
long start = System.currentTimeMillis();
try {
list.forEach(s -> {
if (s.getId() == 5000L) {
throw new RuntimeException("exception");
}
s.setTestStr("test_str5");
mapper.updateById(s);
});
} catch (Throwable e) {
System.out.println("更新失败!");
flag.set(true);
} finally {
// 切换回主线程执行
countDownLatch.countDown();
}
try {
// 等待主线程执行
mainLatch.await();
} catch (Throwable e) {
System.out.println("主线程超时!");
flag.set(true);
}
if (flag.get()) {
long end = System.currentTimeMillis();
System.out.println("子线程回滚：" + Thread.currentThread().getName() + "耗时:" + (end - start));
dataSourceTransactionManager.rollback(transactionStatus);
} else {
long end = System.currentTimeMillis();
System.out.println("子线程提交：" + Thread.currentThread().getName() + "耗时:" + (end - start));
dataSourceTransactionManager.commit(transactionStatus);
}
}
