System Error occurs when we click on the Cloud Migration Assistant
Asked by Sunil kumar:

While opening the confluence server migration Assistant the below error.

##############################################################

Oops - an error has occurred

[](http://hub.carrier.utc.com/)System Error

A system error has occurred --- our apologies!

For immediate troubleshooting, consult our [**knowledge base**](http://confluence.atlassian.com/display/CONFKB/Confluence+Knowledge+Base+Home) for a solution.

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1. a description of your problem and what you were doing at the time it occurred
2. a copy of the error and system information found below
3. a copy of the application logs (if possible).

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Cause

org.apache.velocity.exception.MethodInvocationException: Invocation of method 'getInitialState' in class com.atlassian.migration.agent.web.AppAction threw exception com.atlassian.util.concurrent.LazyReference$InitializationException: javax.persistence.PersistenceException: Failed to update database schema at /templates/app.vm\[line 21, column 44\]  
at org.apache.velocity.runtime.parser.node.ASTIdentifier.execute(ASTIdentifier.java:223)

caused by: com.atlassian.util.concurrent.LazyReference$InitializationException: javax.persistence.PersistenceException: Failed to update database schema  
at com.atlassian.util.concurrent.LazyReference.getInterruptibly(LazyReference.java:149)

caused by: javax.persistence.PersistenceException: Failed to update database schema  
at com.atlassian.migration.agent.store.jpa.impl.LiquibaseSchemaUpgrader.upgrade(LiquibaseSchemaUpgrader.java:35)

caused by: liquibase.exception.LockException: Could not acquire change log lock. Currently locked by 172.31.214.58 (172.31.214.58) since 1/23/20 3:17 PM  
at liquibase.lockservice.StandardLockService.waitForLock(StandardLockService.java:230)


Answers:
author: Sevag Keoshgerian
body: Hi [@Sunil kumar](/t5/user/viewprofilepage/user-id/4447826)

Can you attach a screenshot of the page with the problem. It sounds similar to a problem I came across and the way that I fixed it was through dropping a table from the DB.

Here are the steps:

1. Shutdown confluence server

2. Drop table mig_check_override from the database

3. Restart Confluence Server

comments: author: Sunil kumar
body: Hi [@Sevag Keoshgerian](/t5/user/viewprofilepage/user-id/4661450) ,

Shared the attach screen shot for your reference.

![Cloud Migration.PNG](https://community.atlassian.com/t5/image/serverpage/image-id/248110i43B9E270336A8C7A/image-size/large?v=v2&px=999 "Cloud Migration.PNG")


author: Fabio Racobaldo _Herzum_
body: Hi [@Sunil kumar](/t5/user/viewprofilepage/user-id/4447826) ,

please could you provide us information about DB linked to your instance. This issue usually happens with H2 embedded database.

Take a look here <https://community.atlassian.com/t5/Confluence-questions/Atlassian-Cloud-Migration-Assistance-is-giving-error-while/qaq-p/1196608>

Fabio

comments: author: Sunil kumar
body: Hi [@Fabio Racobaldo _Herzum_](/t5/user/viewprofilepage/user-id/781528) ,

Please find the below details of the DB linked -

Database name - PostgreSQL  
Database version - 9.6.23  
Database Dialect - com.atlassian.confluence.impl.hibernate.dialect.PostgreSQLDialect  
Database Driver Name - org.postgresql.Driver  
Database Driver Version - 42.1.1  
Database Connection URL - jdbc:postgresql://localhost:5432/confluence  
Database Connection Transaction Isolation - Read committed  
Database Latency - 1


author: Sunil kumar
body: [@Fabio Racobaldo _Herzum_](/t5/user/viewprofilepage/user-id/781528) , Did you get any chance to look in the issue , awating for your response.


Tags: confluence-server

migration-customer-care

server