Lock wait timeout exceeded try restarting transaction

There have been frequent occurrences in recent projects   Lock wait timeout exceeded; try restarting transaction This mistake , It makes us miserable , To solve the problem , Find a lot of information on the Internet , Finally, the problem reappears . The specific operation steps are as follows （ I use mysql The tool is  navicat）：

First step ： Turn on sql Command page

The second step ： Input start transaction; Start a transaction

The third step ： Input update sentence   UPDATE TABLENAME set time=null where id=29163;（ Remember not to   Submit （commit;））

Step four ： Writing tests

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​​public​​​ ​​class​​​ ​​StTest ​​​​implements​​​ ​​Runnable{​​ ​​private​​​  ​​static​​​ ​​ApplicationContext applicationContext=​​​​null​​​​;​​ ​​private​​​ ​​static​​​ ​​AtomicInteger a=​​​​new​​​ ​​AtomicInteger(​​​​0​​​​);​​ ​​static​​​ ​​{​​ ​​applicationContext=​​​​new​​​ ​​ClassPathXmlApplicationContext(​​​​"classpath:application.xml"​​​​);​​ ​​}​​ ​​public​​​ ​​static​​​ ​​void​​​ ​​main(String[] args) ​​​​throws​​​ ​​Exception {​​ ​​ExecutorService executorService = Executors.newFixedThreadPool(​​​​10​​​​);​​ ​​for​​​ ​​(​​​​int​​​ ​​i = ​​​​0​​​​; i <​​​​10​​​ ​​; i++) {​​ ​​executorService.execute(​​​​new​​​ ​​aaaa());​​ ​​}​​ ​​if​​​​(!executorService.isTerminated()){​​ ​​executorService.shutdown();​​ ​​}​​ ​​}​​ ​​@Override​​ ​​public​​​ ​​void​​​ ​​run() {​​ ​​XXXService bean = applicationContext.getBean(XXXService.​​​​class​​​​);​​ ​​XXXBeand xx= ​​​​null​​​​;​​ ​​try​​​ ​​{​​ ​​xx= bean.byId(​​​​254213​​​​);​​ ​​} ​​​​catch​​​ ​​(Exception e) {​​ ​​e.printStackTrace();​​ ​​}​​ ​​long​​​ ​​aaa=System.currentTimeMillis();​​ ​​for​​​ ​​(​​​​int​​​ ​​i = ​​​​0​​​​; i < ​​​​10​​​​; i++) {​​ ​​try​​​ ​​{​​ ​​bean.update(xx);​​ ​​} ​​​​catch​​​ ​​(Exception e) {​​ ​​e.printStackTrace();​​ ​​}​​ ​​}​​ ​​System.out.println(System.currentTimeMillis()-aaa);​​ ​​}​​ ​​}​​

Run the program and run the following 3 individual sql View results

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​​SELECT * FROM information_schema.INNODB_TRX;​​ ​​select * from information_schema.innodb_lock_waits;​​ ​​select * from information_schema.innodb_locks;​​

　　 Get the following run results . We found several others  trx_state  Status is LOCK WAIT, Get the result we want to reproduce

 

Step five ： Wait for the error to appear , After waiting for a period of time, we will find that the program reports an error

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​​Caused by: java.sql.SQLException: Lock wait timeout exceeded; ​​​​try​​​ ​​restarting transaction​​ ​​at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:​​​​1055​​​​)​​ ​​at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:​​​​956​​​​)​​ ​​at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:​​​​3491​​​​)​​ ​​at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:​​​​3423​​​​)​​ ​​at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:​​​​1936​​​​)​​ ​​at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:​​​​2060​​​​)​​ ​​at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:​​​​2542​​​​)​​ ​​at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:​​​​1734​​​​)​​ ​​at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:​​​​995​​​​)​​ ​​at com.alibaba.druid.pool.DruidPooledPreparedStatement.execute(DruidPooledPreparedStatement.java:​​​​493​​​​)​​ ​​at sun.reflect.GeneratedMethodAccessor21.invoke(Unknown Source)​​ ​​at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:​​​​43​​​​)​​ ​​at java.lang.reflect.Method.invoke(Method.java:​​​​606​​​​)​​ ​​at org.apache.ibatis.logging.jdbc.PreparedStatementLogger.invoke(PreparedStatementLogger.java:​​​​55​​​​)​​ ​​at com.sun.proxy.$Proxy17.execute(Unknown Source)​​ ​​at org.apache.ibatis.executor.statement.PreparedStatementHandler.update(PreparedStatementHandler.java:​​​​41​​​​)​​ ​​at org.apache.ibatis.executor.statement.RoutingStatementHandler.update(RoutingStatementHandler.java:​​​​66​​​​)​​ ​​at org.apache.ibatis.executor.SimpleExecutor.doUpdate(SimpleExecutor.java:​​​​45​​​​)​​ ​​at org.apache.ibatis.executor.BaseExecutor.update(BaseExecutor.java:​​​​100​​​​)​​ ​​at org.apache.ibatis.executor.CachingExecutor.update(CachingExecutor.java:​​​​75​​​​)​​ ​​at sun.reflect.GeneratedMethodAccessor35.invoke(Unknown Source)​​ ​​at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:​​​​43​​​​)​​ ​​at java.lang.reflect.Method.invoke(Method.java:​​​​606​​​​)​​ ​​at org.apache.ibatis.plugin.Plugin.invoke(Plugin.java:​​​​59​​​​)​​ ​​at com.sun.proxy.$Proxy15.update(Unknown Source)​​ ​​at org.apache.ibatis.session.defaults.DefaultSqlSession.update(DefaultSqlSession.java:​​​​148​​​​)​​ ​​at sun.reflect.GeneratedMethodAccessor34.invoke(Unknown Source)​​ ​​at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:​​​​43​​​​)​​ ​​at java.lang.reflect.Method.invoke(Method.java:​​​​606​​​​)​​ ​​at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:​​​​354​​​​)​​ ​​... ​​​​20​​​ ​​more​​

The results obtained from the above , You can know that this error occurs when a transaction is not committed , Other transactions also operate on the same object , So we found the cause of the problem , We can modify it according to this situation .

This is the mistake I encountered this time , Let me share with you , To avoid such a situation in the program .