mybatis-plus全局控制

mybatis-plus:
  configuration:
    # 单个SQL执行超时时间(含insert,delete,select)，一般应用不宜过长，单位秒
    default-statement-timeout: 30

• 超时异常

### Cause: com.mysql.cj.jdbc.exceptions.MySQLTimeoutException: Statement cancelled due to timeout or client request
; Statement cancelled due to timeout or client request; nested exception is com.mysql.cj.jdbc.exceptions.MySQLTimeoutException: Statement cancelled due to timeout or client request
	at org.springframework.jdbc.support.SQLExceptionSubclassTranslator.doTranslate(SQLExceptionSubclassTranslator.java:76)
	at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:72)
	at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:81)
	at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:91)
	at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:441)
	at com.sun.proxy.$Proxy133.selectList(Unknown Source)
	at org.mybatis.spring.SqlSessionTemplate.selectList(SqlSessionTemplate.java:224)

mybatis单个SQL控制

• 写XML 写法，单位秒

<insert  
  id="insert"  
  parameterType="com.test.abc.Person"  
  ...

  timeout="30">
...
</insert>

• Mapper类写法，单位秒

@Mapper
public interface DemoMapper extends BaseMapper<Demo> {

    @Select("SELECT * FROM DEMO")
    @Options(timeout = 30) // 设置超时时间为 30 秒
    List<Demo> select();
}

• 超时异常

同上(略)

spring事务超时控制

• 整个事务的超时时间，单位是秒。
• 它的原理大致是事务启动时，事务上下文会计算一个到期时间deadLine（当前时间+超时时间），当mybatis -> prepareStatement时，会调用 SpringManagedTransaction 的getTimeOut，该方法会计算事务剩余时间timeToLiveInSeconds（deadLine-System.currentTimeMillis()），如果timeToLiveInSeconds小于0则报错TransactionTimedOutException，大于0根据情况设置为statement 的queryTimeOut （参照下文的源码分析）

情况1：事务剩余时间 timeToLiveInSeconds小于 statement 本身的 queryTimeOut，则 statement 的 setQueryTimeout 设置为 timeToLiveInSeconds

情况2: 事务剩余时间 timeToLiveInSeconds大于 statement 本身的 queryTimeOut，则 statement 的 setQueryTimeout 设置为 queryTimeOut

@Transactional(timeout = 15)
public int test(){
	demoMapper.select();

	demoMapper.insert(...);
	
	// 其他数据库操作
}

根据它的原理及测试，可能会出现以下两种异常。

• 事务超时异常： TransactionTimedOutException

org.springframework.transaction.TransactionTimedOutException: Transaction timed out: deadline was Thu Dec 14 16:06:47 CST 2023
	at org.springframework.transaction.support.ResourceHolderSupport.checkTransactionTimeout(ResourceHolderSupport.java:155)
	at org.springframework.transaction.support.ResourceHolderSupport.getTimeToLiveInMillis(ResourceHolderSupport.java:144)
	at org.springframework.transaction.support.ResourceHolderSupport.getTimeToLiveInSeconds(ResourceHolderSupport.java:128)
	at org.mybatis.spring.transaction.SpringManagedTransaction.getTimeout(SpringManagedTransaction.java:125)
	at org.apache.ibatis.executor.SimpleExecutor.prepareStatement(SimpleExecutor.java:87)
	at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:62)

• statement执行超时异常： MySQLTimeoutException

com.mysql.cj.jdbc.exceptions.MySQLTimeoutException: Statement cancelled due to timeout or client request
	at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:113)
	at com.mysql.cj.jdbc.ClientPreparedStatement.executeInternal(ClientPreparedStatement.java:955)
	at com.mysql.cj.jdbc.ClientPreparedStatement.execute(ClientPreparedStatement.java:372)
	at com.zaxxer.hikari.pool.ProxyPreparedStatement.execute(ProxyPreparedStatement.java:44)
	at com.zaxxer.hikari.pool.HikariProxyPreparedStatement.execute(HikariProxyPreparedStatement.java)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.apache.ibatis.logging.jdbc.PreparedStatementLogger.invoke(PreparedStatementLogger.java:59)
	at com.sun.proxy.$Proxy197.execute(Unknown Source)
	at org.apache.ibatis.executor.statement.PreparedStatementHandler.query(PreparedStatementHandler.java:64)

JDBC也可以配置socket超时时间

• 配置socketTimeout 单位毫秒，一般不推荐配这个

jdbc:mysql://localhost:3066/testdb?useUnicode=true&characterEncoding=utf8&autoReconnect=true&allowMultiQueries=true&serverTimezone=Asia/Shanghai
&socketTimeout=60000

总结

mybatis 执行SQL超时，底层也是用了 Jdbc 的 Statment 的 setQueryTimeout

mybatis设置超时源码（spring5.2.15+mybatis3.5.9）

BaseStatementHandler.java

public abstract class BaseStatementHandler implements StatementHandler {
  protected void setStatementTimeout(Statement stmt, Integer transactionTimeout) throws SQLException {
    Integer queryTimeout = null;
    if (mappedStatement.getTimeout() != null) {
      queryTimeout = mappedStatement.getTimeout();
    } else if (configuration.getDefaultStatementTimeout() != null) {
      queryTimeout = configuration.getDefaultStatementTimeout();
    }
    if (queryTimeout != null) {
      stmt.setQueryTimeout(queryTimeout);
    }
    StatementUtil.applyTransactionTimeout(stmt, queryTimeout, transactionTimeout);
  }

StatementUtil.java

public class StatementUtil {

  private StatementUtil() {
    // NOP
  }

  /**
   * Apply a transaction timeout.
   * <p>
   * Update a query timeout to apply a transaction timeout.
   * </p>
   * @param statement a target statement
   * @param queryTimeout a query timeout
   * @param transactionTimeout a transaction timeout
   * @throws SQLException if a database access error occurs, this method is called on a closed <code>Statement</code>
   */
  public static void applyTransactionTimeout(Statement statement, Integer queryTimeout, Integer transactionTimeout) throws SQLException {
    if (transactionTimeout == null) {
      return;
    }
    // 事务剩余时间小于 statement自己的queryTimeout，就用事务的剩余时间，所以在事务里面statement的超时时间是动态的。
    if (queryTimeout == null || queryTimeout == 0 || transactionTimeout < queryTimeout) {
      statement.setQueryTimeout(transactionTimeout);
    }
  }

}

jdbc 测试代码

try (Connection connection = dataSource.getConnection()) {
            // 创建 Statement 对象
            Statement statement = connection.createStatement();

            // 设置查询超时时间为 10 秒
            int timeoutInSeconds = 10;
            statement.setQueryTimeout(timeoutInSeconds);

            // 执行查询
            String sqlQuery = "SELECT sleep(12)";
            ResultSet resultSet = statement.executeQuery(sqlQuery);

            // 处理结果集
            while (resultSet.next()) {
                // 处理每一行数据
            }

            resultSet.close();
            statement.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }