Liquibase锁 - 原因？

Question

我在针对Oracle服务器运行大量liquibase脚本时得到了这个.有些电脑是我.

Waiting for changelog lock....
Waiting for changelog lock....
Waiting for changelog lock....
Waiting for changelog lock....
Waiting for changelog lock....
Waiting for changelog lock....
Waiting for changelog lock....
Liquibase Update Failed: Could not acquire change log lock.  Currently locked by SomeComputer (192.168.15.X) since 2013-03-20 13:39
SEVERE 2013-03-20 16:59:liquibase: Could not acquire change log lock.  Currently locked by SomeComputer (192.168.15.X) since 2013-03-20 13:39
liquibase.exception.LockException: Could not acquire change log lock.  Currently locked by SomeComputer (192.168.15.X) since 2013-03-20 13:39
        at liquibase.lockservice.LockService.waitForLock(LockService.java:81)
        at liquibase.Liquibase.tag(Liquibase.java:507)
        at liquibase.integration.commandline.Main.doMigration(Main.java:643)
        at liquibase.integration.commandline.Main.main(Main.java:116)

可能会达到同时进行的会话/交易次数吗？有人有什么想法吗？

Answer 1

有时,如果更新应用程序突然停止,则锁定仍然卡住.

然后跑

UPDATE DATABASECHANGELOGLOCK SET LOCKED=FALSE, LOCKGRANTED=null, LOCKEDBY=null where ID=1;

对数据库的帮助.

或者您可以简单地删除DATABASECHANGELOGLOCK表,它将被重新创建.

Answer 2

这可能是由于一个被杀死的liquibase进程未在DATABASECHANGELOGLOCK表上释放其锁定.然后,

DELETE FROM DATABASECHANGELOGLOCK;

可能会帮助你.

编辑: @Adrian Ber的答案提供了比这更好的解决方案.只有在解决问题时遇到任何问题才能执行此操作.

Answer 3

问题是Liquibase中的SequenceExists的错误实现.由于这些陈述的变更集需要很长时间,并且意外中止.然后下一次尝试执行liquibase-scripts锁定.

  <changeSet author="user" id="123">
    <preConditions onFail="CONTINUE">
      <not><sequenceExists sequenceName="SEQUENCE_NAME_SEQ" /></not>
    </preConditions>
    <createSequence sequenceName="SEQUENCE_NAME_SEQ"/>
  </changeSet>

解决方法是使用纯SQL来检查:

  <changeSet author="user" id="123">
    <preConditions onFail="CONTINUE">
            <sqlCheck expectedResult="0">
              select count(*) from user_sequences where sequence_name = 'SEQUENCE_NAME_SEQ';
            </sqlCheck>
    </preConditions>
    <createSequence sequenceName="SEQUENCE_NAME_SEQ"/>
  </changeSet>

Lockdata存储在表DATABASECHANGELOCK中.要摆脱锁定,只需将1更改为0或删除该表并重新创建.

Answer 4

您可以手动或使用查询安全地删除表。它将自动重新创建。

DROP TABLE DATABASECHANGELOGLOCK;

Answer 5

没有提到哪个环境用于执行Liquibase。如果是Spring Boot 2，则可以扩展liquibase.lockservice.StandardLockService而无需运行直接得多的SQL语句。例如：

/**
 * This class is enforcing to release the lock from the database.
 *
 */
 public class ForceReleaseLockService extends StandardLockService {

    @Override
    public int getPriority() {
        return super.getPriority()+1;
    }

    @Override
    public void waitForLock() throws LockException {
        try {
            super.forceReleaseLock();
        } catch (DatabaseException e) {
            throw new LockException("Could not enforce getting the lock.", e);
        }
        super.waitForLock();
    }
}

该代码正在强制释放锁。这在测试设置中很有用，在测试设置中，如果发生错误或调试中止，则可能不会调用release调用。

该类必须放在liquibase.ext包中，并由Spring Boot 2自动配置获取。