@Transactional 上的 MySQL 套接字超时行为

Question

我正在使用 spring-boot (2.3.4.RELEASE) 和 MySQL (8.0.21)。

我在 Spring Boot 中的数据库配置是

spring.datasource.url=jdbc:mysql://localhost:3306/testDB?connectTimeout=2000&socketTimeout=10000&autoReconnect=true&allowMultiQueries=true
spring.datasource.username=root
spring.datasource.password=toor
spring.datasource.dbcp2.test-while-idle=true
spring.datasource.dbcp2.pool-prepared-statements=true
spring.datasource.dbcp2.validation-query=SELECT 1 from dual where @@innodb_read_only = 0
spring.datasource.type=org.apache.commons.dbcp2.BasicDataSource

MySQL 连接器

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.18</version>
</dependency>

DBCP2

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-dbcp2</artifactId>
    <version>2.1.1</version>
</dependency>

我测试了以下代码模板并发现了这种奇怪的行为

@Autowired
private NamedParameterJdbcTemplate jdbcTemplate;

@Transactional
public void f1() {
  jdbcTemplate.queryForObject("SELECT sleep(12)", new HashMap<>(), Integer.class);
}

@Autowired
private NamedParameterJdbcTemplate jdbcTemplate;

@Transactional
public void f2() {
  Thread.sleep(12000);
  jdbcTemplate.queryForObject("SELECT count(*) from my_table", new HashMap<>(), Integer.class);
}

第一个函数给出了这个错误：

11:10:07.862 [qtp262911569-27] ERROR o.s.t.i.TransactionInterceptor - Application exception overridden by rollback exception
org.springframework.dao.RecoverableDataAccessException: PreparedStatementCallback; SQL [SELECT sleep(12)]; Communications link failure

The last packet successfully received from the server was 10,013 milliseconds ago. The last packet sent successfully to the server was 10,013 milliseconds ago.; nested exception is com.MySQL.cj.jdbc.exceptions.CommunicationsException: Communications link failure

The last packet successfully received from the server was 10,013 milliseconds ago. The last packet sent successfully to the server was 10,013 milliseconds ago.
at org.springframework.jdbc.support.SQLExceptionSubclassTranslator.doTranslate(SQLExceptionSubclassTranslator.java:100)
at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:72)
at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:81)
at org.springframework.jdbc.core.JdbcTemplate.translateException(JdbcTemplate.java:1443)
at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:633)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:669)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:694)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:748)
at org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate.queryForObject(NamedParameterJdbcTemplate.java:236)
at org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate.queryForObject(NamedParameterJdbcTemplate.java:245)
at org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate.queryForObject(NamedParameterJdbcTemplate.java:261)

而第二个工作正常。

我知道这与我上面提到的配置中 MySQL URL 中设置为 10 秒的套接字超时有关。但不确定幕后发生了什么。谁能帮助我理解这里发生了什么？

Answer 1

您可以尝试将 application.properties 更改为：-

\n

spring.datasource.testWhileIdle = true\nspring.datasource.timeBetweenEvictionRunsMillis = 60000\nspring.datasource.validationQuery = SELECT 1\n

\n

每分钟（60000 毫秒）将执行执行查询 \xe2\x80\x9cSELECT 1\xe2\x80\x9d 的测试连接。通过这种方式，我们可以保持数据库连接处于活动状态，定期执行验证查询，并避免达到 MySQL\xe2\x80\x99s wait_timeout。

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