Could not retrieve transation read-only status server 的解决办法

问题描述：

    在项目开发的过程中，使用Hibernate的ORM进行建表时，出现 “ Could not retrieve transation read-only status server ”的异常，无法进行表的创建的操作，具体异常内容如下：

org.activiti.engine.ActivitiException: couldn't create db schema: create table ACT_GE_PROPERTY ( 

NAME_ varchar(64), 
VALUE_ varchar(300), 
REV_ integer, 
primary key (NAME_) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE utf8_bin
at org.activiti.engine.impl.db.DbSqlSession.executeSchemaResource(DbSqlSession.java:1242)
at org.activiti.engine.impl.db.DbSqlSession.executeSchemaResource(DbSqlSession.java:1138)
at org.activiti.engine.impl.db.DbSqlSession.executeMandatorySchemaResource(DbSqlSession.java:897)
at org.activiti.engine.impl.db.DbSqlSession.dbSchemaCreateEngine(DbSqlSession.java:874)
at org.activiti.engine.impl.db.DbSqlSession.dbSchemaUpdate(DbSqlSession.java:952)
at org.activiti.engine.impl.db.DbSqlSession.performSchemaOperationsProcessEngineBuild(DbSqlSession.java:1318)
at org.activiti.engine.impl.SchemaOperationsProcessEngineBuild.execute(SchemaOperationsProcessEngineBuild.java:28)
at org.activiti.engine.impl.interceptor.CommandInvoker$1.run(CommandInvoker.java:37)
at org.activiti.engine.impl.interceptor.CommandInvoker.executeOperation(CommandInvoker.java:78)
at org.activiti.engine.impl.interceptor.CommandInvoker.executeOperations(CommandInvoker.java:57)
at org.activiti.engine.impl.interceptor.CommandInvoker.execute(CommandInvoker.java:42)
at org.activiti.engine.impl.interceptor.TransactionContextInterceptor.execute(TransactionContextInterceptor.java:48)
at org.activiti.engine.impl.interceptor.CommandContextInterceptor.execute(CommandContextInterceptor.java:63)
at org.activiti.engine.impl.interceptor.LogInterceptor.execute(LogInterceptor.java:35)
at org.activiti.engine.impl.cfg.CommandExecutorImpl.execute(CommandExecutorImpl.java:44)
at org.activiti.engine.impl.ProcessEngineImpl.(ProcessEngineImpl.java:81)
at org.activiti.engine.impl.cfg.ProcessEngineConfigurationImpl.buildProcessEngine(ProcessEngineConfigurationImpl.java:665)
at etc.TActiviti.createActivitiTables(TActiviti.java:56)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
Caused by: java.sql.SQLException: Could not retrieve transation read-only status server
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1094)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:997)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:983)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:928)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:959)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:949)
at com.mysql.jdbc.ConnectionImpl.isReadOnly(ConnectionImpl.java:3967)
at com.mysql.jdbc.ConnectionImpl.isReadOnly(ConnectionImpl.java:3938)
at com.mysql.jdbc.StatementImpl.execute(StatementImpl.java:814)
at com.mysql.jdbc.StatementImpl.execute(StatementImpl.java:791)
at org.activiti.engine.impl.db.DbSqlSession.executeSchemaResource(DbSqlSession.java:1216)
... 40 more
Caused by: java.sql.SQLException: Unknown system variable 'tx_read_only'
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1094)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4208)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4140)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2597)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2758)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2820)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2769)
at com.mysql.jdbc.StatementImpl.executeQuery(StatementImpl.java:1569)
at com.mysql.jdbc.ConnectionImpl.isReadOnly(ConnectionImpl.java:3961)

... 44 more

问题分析：

    导致这个异常的情况有两种：

    一种情况为：使用MySql数据库服务为最新版本8.0.11，而在项目开发的过程中使用了低版本的MySql驱动包。

   二种情况为： 当MySQL的数据库隔离级别为REPEATABLE-READ时，查询一个select语句也算是事物的开始，而且在hibernate里会把以select语句开头的事务标记为只读事务，此时在这个事务里再执行insert、update、delete等DML语句就会出现如上的异常信息。

解决方案：

解决方案一：

    修改项目中MySQL数据库驱动包，将版本选择为与当前数据库服务器版本相同的版本，如果是Maven项目，则在pom.xml的配置文件中，键入如下内容：

	
		mysql
		mysql-connector-java
		${mysql-connector-java.version}
	

注意：${mysql-connector-java.version} 为自己匹配的版本号！！！

如果为普通Web项目，我这儿提供了几个常用版本的MySQL驱动下载，点击下面连接进行下载：

https://download.csdn.net/download/hello_world_qwp/10473266

解决方案二：

    通过修改MySQL的事务隔离级别实现，查看当前MySQL数据库的事务隔离级别，输入命令 “ show variables like 'transaction_%'; ” ，如下图：

    将隔离级别修改为 -> READ-COMMITTED 即可，输入命令 “ SET GLOBAL transaction_isolation='READ-COMMITTED'; ” 即可解决该问题了。

注：如果要永久的生效，则需要在MySQL的初始化配置文件中进行配置，如下图：

   好了，关于 Could not retrieve transation read-only status server 的解决办法 就写到这儿了，如果还有什么疑问或遇到什么问题欢迎扫码提问，也可以给我留言哦，我会一一详细的解答的。
歇后语：“ 共同学习，共同进步 ”，也希望大家多多关注CSND的IT社区。