Summary

The Space XML backup fails and results in a java.lang.ClassCastException error.

Environment

Confluence Data Center

Diagnosis

The application log, atlassian-confluence.log, will display WARN messages indicating the following exception: java.lang.ClassCastException: class java.lang.Long cannot be cast to class java.lang.Integer.

2024-04-10 02:54:37,669 WARN [ConfluenceBackupRestoreManager:thread-24] [confluence.impl.backuprestore.ConfluenceBackupRestoreManager] updateJobStateAfterCompletion Backup restore job BackupRestoreJob{id=1008762890, jobOperation=BACKUP, jobScope=SPACE, jobState=PROCESSING, createTime=2024-04-10T07:54:36Z, startProcessingTime=2024-04-10T07:54:36Z, finishProcessingTime=null, cancelTime=null, owner='abcd', whoCancelledTheJob='null', errorMessage='null'} failed: java.util.concurrent.ExecutionException: java.lang.ClassCastException: class java.lang.Long cannot be cast to class java.lang.Integer (java.lang.Long and java.lang.Integer are in module java.base of loader 'bootstrap')
 -- url: /docs/rest/api/backup-restore/backup/space | userName: abcd | referer: https://abc.xyz.com/docs/plugins/xxxx/xxx | traceId: e45daeca248a11dd

Check the data types for the columns in the `content` and `contentproperties` tables. The columns `child_position`, `draftpageversion`, and `version` should all be of the integer data type.

Cause

The issue can be due to a change in the data type of the columns in the content and contentproperties tables; however, the reason for the change was unclear in this scenario.

Solution

To resolve this issue, follow these steps to change the data type of the columns to integer for the content and contentproperties tables:

1. Shutdown Confluence
2. Take full backup of Confluence DB.

3. Execute below SQL command to alter the datatype. 

   • PostgreSQL
   • MySQL
   • SQL Server

   alter table content 
   alter column child_position type integer,
   alter column version type integer,
   alter column draftpageversion type integer;

   ALTER TABLE CONTENT 
     MODIFY COLUMN hibernateversion integer,
     MODIFY COLUMN child_position integer,
     MODIFY COLUMN version integer,
     MODIFY COLUMN draftpageversion integer;

   ALTER TABLE CONTENT
     ALTER COLUMN CHILD_POSITION INT;
   
   ALTER TABLE CONTENT
     ALTER COLUMN VERSION INT;
   
   ALTER TABLE CONTENT
     ALTER COLUMN DRAFTPAGEVERSION INT;

   Note : Only alter those columns which are NOT having integer data type.

4. Start Confluence 

5. Verify the Space XML backup