工作日常-SQL不能乱写
前言：刚接手别人的项目没多久，在昨天的一次上线中无故躺坑，且该大兄弟已经离职，不得不帮他填坑，整完后，今天想搞一个总结，结论就是：SQL不能乱写。
搜索关键词：Cause: java.sql.SQLException: Unknown thread id: 1
参考文章：//blog.csdn.net/weixin_42340670/article/details/88587118
问题背景，接手的一个项目中，有一个 service 类姑且叫 ServiceA ，在 ServiceA 中依赖一个类 @Autowired ServiceB，而 ServiceB 创建后有一个初始化方法 @PostConstruct init()，在这个方法中一路调用来到了 dao 层的一个方法中，该方法中执行了这样一句 sql：
SELECT a.vin, avg( a.kwh_100km ) AS kwh_100km FROM tb_tmp a WHERE kwh_100km > 0 AND EXISTS ( SELECT count( 1 ) FROM tb_tmp WHERE vin = a.vin AND kwh_100km > 0 AND dt > a.dt HAVING count(*) < 7 ) GROUP BY a.vin
这句 sql 执行报错的栈信息如下：
[ERROR] [2021-10-13T17:20:04.774] Application startup failed org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'brainCarServiceImpl': Unsatisfied dependency expressed through field 'd1ScreenService'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'micMonitorD1ScreenServiceImpl': Injection of autowired dependencies failed; nested exception is org.springframework.jdbc.UncategorizedSQLException: ### Error querying database. Cause: java.sql.SQLException: Unknown thread id: 1 ### The error may exist in class path resource [mybatis/mapper/mic/MicEvRunDataDailyMapper.xml] ### The error may involve com.xiaojukeji.iov.mic.biz.dao.mic.MicEvRunDataDailyDao.selectD1CarRecord-Inline ### The error occurred while setting parameters ### SQL: select a.vin, avg(a.kwh_100km) as kwh_100km from tb_tmp a WHERE kwh_100km > 0 and exists ( select count(1) from tb_tmp where vin = a.vin and kwh_100km > 0 and dt > a.dt having count(*) < 7 ) group by a.vin ### Cause: java.sql.SQLException: Unknown thread id: 1 ; uncategorized SQLException for SQL []; SQL state [HY000]; error code [1094]; Unknown thread id: 1; nested exception is java.sql.SQLException: Unknown thread id: 1 at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:588) at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:366) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1264) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:761) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:867) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543) at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693) at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360) at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) at org.springframework.boot.SpringApplication.run(SpringApplication.java:1118) at org.springframework.boot.SpringApplication.run(SpringApplication.java:1107) at com.xiaojukeji.iov.mic.biz.IovMicBizApplication.main(IovMicBizApplication.java:28) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48) at org.springframework.boot.loader.Launcher.launch(Launcher.java:87) at org.springframework.boot.loader.Launcher.launch(Launcher.java:50) at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51) Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'micMonitorD1ScreenServiceImpl': Injection of autowired dependencies failed; nested exception is org.springframework.jdbc.UncategorizedSQLException: ### Error querying database. Cause: java.sql.SQLException: Unknown thread id: 1 ### The error may exist in class path resource [mybatis/mapper/mic/MicEvRunDataDailyMapper.xml] ### The error may involve com.xiaojukeji.iov.mic.biz.dao.mic.MicEvRunDataDailyDao.selectD1CarRecord-Inline ### The error occurred while setting parameters ### SQL: select a.vin, avg(a.kwh_100km) as kwh_100km from mic_ev_run_data_daily a WHERE kwh_100km > 0 and exists ( select count(1) from mic_ev_run_data_daily where vin = a.vin and kwh_100km > 0 and dt > a.dt having count(*) < 7 ) group by a.vin ### Cause: java.sql.SQLException: Unknown thread id: 1 ; uncategorized SQLException for SQL []; SQL state [HY000]; error code [1094]; Unknown thread id: 1; nested exception is java.sql.SQLException: Unknown thread id: 1 at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:372) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1264) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:208) at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066) at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:585) ... 27 common frames omitted Caused by: org.springframework.jdbc.UncategorizedSQLException: ### Error querying database. Cause: java.sql.SQLException: Unknown thread id: 1 ### The error may exist in class path resource [mybatis/mapper/mic/MicEvRunDataDailyMapper.xml] ### The error may involve com.xiaojukeji.iov.mic.biz.dao.mic.MicEvRunDataDailyDao.selectD1CarRecord-Inline ### The error occurred while setting parameters ### SQL: select a.vin, avg(a.kwh_100km) as kwh_100km from mic_ev_run_data_daily a WHERE kwh_100km > 0 and exists ( select count(1) from mic_ev_run_data_daily where vin = a.vin and kwh_100km > 0 and dt > a.dt having count(*) < 7 ) group by a.vin ### Cause: java.sql.SQLException: Unknown thread id: 1 ; uncategorized SQLException for SQL []; SQL state [HY000]; error code [1094]; Unknown thread id: 1; nested exception is java.sql.SQLException: Unknown thread id: 1 at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:84) at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:81) at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:81) at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:73) at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:446) at com.sun.proxy.$Proxy112.selectList(Unknown Source) at org.mybatis.spring.SqlSessionTemplate.selectList(SqlSessionTemplate.java:230) at org.apache.ibatis.binding.MapperMethod.executeForMany(MapperMethod.java:137) at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:75) at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:59) at com.sun.proxy.$Proxy159.selectD1CarRecord(Unknown Source) at com.xiaojukeji.iov.mic.biz.task.MicD1LabelTask.queryEv(MicD1LabelTask.java:258) at com.xiaojukeji.iov.mic.biz.task.MicD1LabelTask.setDataLabelDTOList(MicD1LabelTask.java:143) at com.xiaojukeji.iov.mic.biz.task.MicD1LabelTask.getD1LableMap(MicD1LabelTask.java:71) at com.xiaojukeji.iov.mic.biz.service.impl.MicMonitorD1ScreenServiceImpl.init(MicMonitorD1ScreenServiceImpl.java:311) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredMethodElement.inject(AutowiredAnnotationBeanPostProcessor.java:701) at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:366) ... 38 common frames omitted Caused by: java.sql.SQLException: Unknown thread id: 1 at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:964) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3973) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3909) at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2527) at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2680) at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2497) at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2455) at com.mysql.jdbc.StatementImpl.executeInternal(StatementImpl.java:839) at com.mysql.jdbc.StatementImpl.execute(StatementImpl.java:739) at com.mysql.jdbc.StatementImpl$CancelTask$1.run(StatementImpl.java:117)
直接带来的结果就是 ServiceB 初始化失败，然后 ServiceA 注入失败，程序启动失败。
按照日志中的语句 Cause: java.sql.SQLException: Unknown thread id: 1 搜索到上面的文章，然后去检查sql,测试环境没问题，然后拿到生产环境，对sql稍加修改如下，执行全量查询报错：
SELECT COUNT(*) FROM ( SELECT a.vin, avg( a.kwh_100km ) AS kwh_100km FROM tb_tmp a WHERE kwh_100km > 0 AND EXISTS ( SELECT count( 1 ) FROM tb_tmp WHERE vin = a.vin AND kwh_100km > 0 AND dt > a.dt HAVING count(*) < 7 ) GROUP BY a.vin ) AS tmp
生产环境执行结果：
ERROR 3024 (HY000): Query execution was interrupted, maximum statement execution time exceeded
由此可判断是sql执行超时所致。
解决方案：try-catch ，避免该异常影响初始化动作。(后面改写 sql ,这样只是为了尽快恢复线上服务)
问题难点：框架异常封装掩盖了原始的sql异常信息，真实的sql异常信息是 执行超时后sql执行任务取消
最后，去线上看一下对应数据量：8392727
最开始的时候数据量小，上面的 sql 执行没问题，中间经过一个多月数据量上来后问题就出来了，而我就是要去帮别人填坑的人，坑啊。
总结两个坑：
1、SQL乱写，不考虑数据量起来后的问题。
2、Mybatis框架封装的异常信息也是坑，吞没了真正有用的异常信息，给出一堆不相关的信息。
