【MyBatis】saveBatch 性能调优

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作者:Natee

最近在压测一批接口，发现接口处理速度慢的有点超出预期，感觉很奇怪，后面定位发现是数据库批量保存这块很慢。

这个项目用的是 mybatis-plus，批量保存直接用的是 mybatis-plus 提供的 saveBatch。我点进去看了下源码，感觉有点不太对劲：

继续追踪了下，从这个代码来看，确实是 for 循环一条一条执行了 sqlSession.insert，下面的 consumer 执行的就是上面的 sqlSession.insert：

然后累计一定数量后，一批 flush。从这点来看，这个 saveBach 的性能肯定比直接一条一条 insert 快。

我直接进行一个粗略的实验，简单创建了一张表来对比一波！

1、1000条数据，一条一条插入

@Test
void MybatisPlusSaveOne() {
    SqlSession sqlSession = sqlSessionFactory.openSession();
    try {
        StopWatch stopWatch = new StopWatch();
        stopWatch.start("mybatis plus save one");
        for (int i = 0; i < 1000; i++) {
            OpenTest openTest = new OpenTest();
            openTest.setA("a" + i);
            openTest.setB("b" + i);
            openTest.setC("c" + i);
            openTest.setD("d" + i);
            openTest.setE("e" + i);
            openTest.setF("f" + i);
            openTest.setG("g" + i);
            openTest.setH("h" + i);
            openTest.setI("i" + i);
            openTest.setJ("j" + i);
            openTest.setK("k" + i);
            //一条一条插入
            openTestService.save(openTest);
        }
        sqlSession.commit();
        stopWatch.stop();
        log.info("mybatis plus save one：" + stopWatch.getTotalTimeMillis());
    } finally {
        sqlSession.close();
    }
}

可以看到，执行一批 1000 条数的批量保存，耗费的时间是 121011 毫秒。

2、1000条数据用 mybatis-plus 自带的 saveBatch 插入

@Test
void MybatisPlusSaveBatch() {
    SqlSession sqlSession = sqlSessionFactory.openSession();
    try {
        List<OpenTest> openTestList = new ArrayList<>();
        for (int i = 0; i < 1000; i++) {
            OpenTest openTest = new OpenTest();
            openTest.setA("a" + i);
            openTest.setB("b" + i);
            openTest.setC("c" + i);
            openTest.setD("d" + i);
            openTest.setE("e" + i);
            openTest.setF("f" + i);
            openTest.setG("g" + i);
            openTest.setH("h" + i);
            openTest.setI("i" + i);
            openTest.setJ("j" + i);
            openTest.setK("k" + i);
            openTestList.add(openTest);
        }
        StopWatch stopWatch = new StopWatch();
        stopWatch.start("mybatis plus save batch");
        //批量插入
        openTestService.saveBatch(openTestList);
        sqlSession.commit();
        stopWatch.stop();
        log.info("mybatis plus save batch：" + stopWatch.getTotalTimeMillis());
    } finally {
        sqlSession.close();
    }
}

耗费的时间是 59927 毫秒，比一条一条插入快了一倍，从这点来看，效率还是可以的。

然后常见的还有一种利用拼接 SQL 方式来实现批量插入，我们也来对比试试看性能如何。

3、1000 条数据用手动拼接 SQL 方式插入，搞个手动拼接：

来跑跑下性能如何：

@Test
void MapperSaveBatch() {
    SqlSession sqlSession = sqlSessionFactory.openSession();
    try {
        List<OpenTest> openTestList = new ArrayList<>();
        for (int i = 0; i < 1000; i++) {
            OpenTest openTest = new OpenTest();
            openTest.setA("a" + i);
            openTest.setB("b" + i);
            openTest.setC("c" + i);
            openTest.setD("d" + i);
            openTest.setE("e" + i);
            openTest.setF("f" + i);
            openTest.setG("g" + i);
            openTest.setH("h" + i);
            openTest.setI("i" + i);
            openTest.setJ("j" + i);
            openTest.setK("k" + i);
            openTestList.add(openTest);
        }
        StopWatch stopWatch = new StopWatch();
        stopWatch.start("mapper save batch");
        //手动拼接批量插入
        openTestMapper.saveBatch(openTestList);
        sqlSession.commit();
        stopWatch.stop();
        log.info("mapper save batch：" + stopWatch.getTotalTimeMillis());
    } finally {
        sqlSession.close();
    }
}

耗时只有 2275 毫秒，性能比 mybatis-plus 自带的 saveBatch 好了 26 倍！

这时，我又突然回想起以前直接用 JDBC 批量保存的接口，那都到这份上了，顺带也跑跑看！

4、1000 条数据用 JDBC executeBatch 插入

@Test
void JDBCSaveBatch() throws SQLException {
    SqlSession sqlSession = sqlSessionFactory.openSession();
    Connection connection = sqlSession.getConnection();
    connection.setAutoCommit(false);

    String sql = "insert into open_test(a,b,c,d,e,f,g,h,i,j,k) values(?,?,?,?,?,?,?,?,?,?,?)";
    PreparedStatement statement = connection.prepareStatement(sql);
    try {
        for (int i = 0; i < 1000; i++) {
            statement.setString(1,"a" + i);
            statement.setString(2,"b" + i);
            statement.setString(3, "c" + i);
            statement.setString(4,"d" + i);
            statement.setString(5,"e" + i);
            statement.setString(6,"f" + i);
            statement.setString(7,"g" + i);
            statement.setString(8,"h" + i);
            statement.setString(9,"i" + i);
            statement.setString(10,"j" + i);
            statement.setString(11,"k" + i);
            statement.addBatch();
        }
        StopWatch stopWatch = new StopWatch();
        stopWatch.start("JDBC save batch");
        statement.executeBatch();
        connection.commit();
        stopWatch.stop();
        log.info("JDBC save batch：" + stopWatch.getTotalTimeMillis());
    } finally {
        statement.close();
        sqlSession.close();
    }
}