問題

An XML backup fails to restore. 

診断

atlassian-confluence.log に次のメッセージが表示される。

 -- referer: http://localhost:8090/setup/setup-restore-start.action | url: /setup/setup-restore.action | userName: anonymous | action: setup-restore
com.atlassian.confluence.importexport.ImportExportException: Unable to complete import: Error while importing backup: could not insert: [com.atlassian.confluence.core.BodyContent#787560]

Caused by: com.mysql.jdbc.PacketTooBigException: Packet for query is too large (17825792 > 16777216 ). You can change this value on the server by setting the max_allowed_packet' variable.

原因

The packet query size exceeds the maximum allowed size that is set in the database configuration, therefore  XML restore process will fail.

ソリューション

In order to resolve this, you will need to check the max_allowed_packet set within the MySQL server:

1. Stop Confluence.

2. Ensure that the size max_allowed_packet parameter is set to 256MB per our Database Setup For MySQL guide:

   max_allowed_packet =256M       

3. Restart the Mysql service.

4. Restart Confluence.