尝试使用Sqoop从BigQuery提取数据时遇到问题。问题是Sqoop流程中存在一个步骤，其中在数据库连接上设置了事务隔离级别。尝试设置TRANSACTION_READ_COMMITTED隔离级别时，Sqoop作业在此步骤失败，并显示以下错误。
2019-06-19 06:45:00,009 - ERROR [main:LoggingUtils@43] - Error executing statement: java.sql.SQLException: [Simba][JDBC](11975) Unsupported transaction isolation level: 2.
java.sql.SQLException: [Simba][JDBC](11975) Unsupported transaction isolation level: 8.
at com.simba.googlebigquery.exceptions.ExceptionConverter.toSQLException(Unknown Source)
at com.simba.googlebigquery.jdbc.common.SConnection.setTransactionIsolation(Unknown Source)
at org.apache.sqoop.manager.SqlManager.makeConnection(SqlManager.java:910)
at org.apache.sqoop.manager.GenericJdbcManager.getConnection(GenericJdbcManager.java:52)
at org.apache.sqoop.manager.SqlManager.execute(SqlManager.java:763)
at org.apache.sqoop.manager.SqlManager.execute(SqlManager.java:786)
at org.apache.sqoop.manager.SqlManager.getColumnInfoForRawQuery(SqlManager.java:289)
at org.apache.sqoop.manager.SqlManager.getColumnTypesForRawQuery(SqlManager.java:260)
at org.apache.sqoop.manager.SqlManager.getColumnTypesForQuery(SqlManager.java:253)
at org.apache.sqoop.manager.ConnManager.getColumnTypes(ConnManager.java:337)
at org.apache.sqoop.orm.ClassWriter.getColumnTypes(ClassWriter.java:1853)
at org.apache.sqoop.orm.ClassWriter.generate(ClassWriter.java:1653)
at org.apache.sqoop.tool.CodeGenTool.generateORM(CodeGenTool.java:107)
at org.apache.sqoop.tool.ImportTool.importTable(ImportTool.java:488)
at org.apache.sqoop.tool.ImportTool.run(ImportTool.java:615)
at org.apache.sqoop.Sqoop.run(Sqoop.java:147)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:76)
at org.apache.sqoop.Sqoop.runSqoop(Sqoop.java:183)
at org.apache.sqoop.Sqoop.runTool(Sqoop.java:225)
at org.apache.sqoop.Sqoop.runTool(Sqoop.java:234)
at org.apache.sqoop.Sqoop.main(Sqoop.java:243)
我还配置了Sqoop以使用TRANSACTION_READ_UNCOMMITTED隔离级别，但出现以下错误
2019-06-19 06:43:48,606 - ERROR [main:LoggingUtils@43] - Error executing statement: java.sql.SQLFeatureNotSupportedException: [Simba][JDBC](10220) Driver does not support this optional feature.
java.sql.SQLFeatureNotSupportedException: [Simba][JDBC](10220) Driver does not support this optional feature.
at com.simba.googlebigquery.exceptions.ExceptionConverter.toSQLException(Unknown Source)
at com.simba.googlebigquery.jdbc.common.SConnection.setAutoCommit(Unknown Source)
at org.apache.sqoop.manager.SqlManager.makeConnection(SqlManager.java:911)
at org.apache.sqoop.manager.GenericJdbcManager.getConnection(GenericJdbcManager.java:52)
at org.apache.sqoop.manager.SqlManager.execute(SqlManager.java:763)
at org.apache.sqoop.manager.SqlManager.execute(SqlManager.java:786)
at org.apache.sqoop.manager.SqlManager.getColumnInfoForRawQuery(SqlManager.java:289)
at org.apache.sqoop.manager.SqlManager.getColumnTypesForRawQuery(SqlManager.java:260)
at org.apache.sqoop.manager.SqlManager.getColumnTypesForQuery(SqlManager.java:253)
at org.apache.sqoop.manager.ConnManager.getColumnTypes(ConnManager.java:337)
at org.apache.sqoop.orm.ClassWriter.getColumnTypes(ClassWriter.java:1853)
at org.apache.sqoop.orm.ClassWriter.generate(ClassWriter.java:1653)
at org.apache.sqoop.tool.CodeGenTool.generateORM(CodeGenTool.java:107)
at org.apache.sqoop.tool.ImportTool.importTable(ImportTool.java:488)
at org.apache.sqoop.tool.ImportTool.run(ImportTool.java:615)
at org.apache.sqoop.Sqoop.run(Sqoop.java:147)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:76)
at org.apache.sqoop.Sqoop.runSqoop(Sqoop.java:183)
at org.apache.sqoop.Sqoop.runTool(Sqoop.java:225)
at org.apache.sqoop.Sqoop.runTool(Sqoop.java:234)
at org.apache.sqoop.Sqoop.main(Sqoop.java:243)