当Liquibase创建它的锁表时，我如何获得此Oracle异常？

Question

我已经安装了DropWizard服务，以便在应用程序启动时自动进行任何液化迁移。

当我第一次启动我的Dropwizard服务时，我运行一个Liquibase::listLocks（）以提供信息。此调用还将创建DATABASE CHANGELOG和DATABASE CHANGELOGLOCK表，如果它们不存在作为副作用。

一旦在新的Oracle ATP DB上，它在调用listLocks期间创建锁表时抛出以下错误：

ERROR 2021-07-08 17:59:22,546  [main] com.blah.utils.LiquibaseMigrator: Error listing locks!
liquibase.exception.DatabaseException: ORA-12838: cannot read/modify an object after modifying it in parallel
 [Failed SQL: (12838) INSERT INTO DATABASECHANGELOGLOCK (ID, LOCKED) VALUES (1, 0)]
    at liquibase.executor.jvm.JdbcExecutor$ExecuteStatementCallback.doInStatement(JdbcExecutor.java:430)
    at liquibase.executor.jvm.JdbcExecutor.execute(JdbcExecutor.java:87)
    at liquibase.executor.jvm.JdbcExecutor.execute(JdbcExecutor.java:159)
    at liquibase.executor.jvm.JdbcExecutor.execute(JdbcExecutor.java:139)
    at liquibase.lockservice.StandardLockService.init(StandardLockService.java:128)
    at liquibase.Liquibase.checkLiquibaseTables(Liquibase.java:1176)
    at liquibase.Liquibase.listLocks(Liquibase.java:1193)
    at com.blah.utils.LiquibaseMigrator.dbLocksExist(LiquibaseMigrator.java:xxx)
    at com.blah.utils.LiquibaseMigratorExecutor.dbLocksExist(LiquibaseMigratorExecutor.java:xxx)
    at com.blah.MyApp.migrateDatabase(MyApp.java:xxx)
    at com.blah.MyApp.run(MyApp.java:xxx)
    at com.blah.MyApp.run(MyApp.java:xxx)
    at io.dropwizard.cli.EnvironmentCommand.run(EnvironmentCommand.java:59)
    at io.dropwizard.cli.ConfiguredCommand.run(ConfiguredCommand.java:98)
    at io.dropwizard.cli.Cli.run(Cli.java:78)
    at io.dropwizard.Application.run(Application.java:94)
    at com.blah.MyApp.main(MyApp.java:xxx)
Caused by: java.sql.SQLException: ORA-12838: cannot read/modify an object after modifying it in parallel

服务将抛出该异常，然后pod将重新启动并重复。我手动将该行添加到它试图插入的锁表中，然后下一次启动成功。

当时只有1个pod在运行，所以我不认为它与我发现的启动错误的种族条件有关，但我不知道为什么/如何它会进入这个无法读取/在并行状态下修改对象后修改它。

Answer 1

确保您正在连接到不使用并行DML的LOW服务