While testing an upgrade from Confluence 6.15 to 7.0.1 beta 1, we can see the following log messages:

1. Upon first login after upgrade:

   2019-09-04 18:25:17,653 WARN [http-nio-8090-exec-2] [confluence.impl.hibernate.ConfluenceHibernateTransactionManager] doCommit Commit failed. Rolling back. Error: Hibernate operation: could not execute statement; sql=n/a; Duplicate entry 'ff8081816cfe2053016cfe22e1e30000' for key 'UK_cxh64nyrevdya903riaky8hs0'; nested exception is com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry 'ff8081816cfe2053016cfe22e1e30000' for key 'UK_cxh64nyrevdya903riaky8hs0'
   

   • UK_cxh64nyrevdya903riaky8hs0 is the unike key on the logininfo table
2. Everytime you publish a page:

   2019-09-04 18:39:02,269 WARN [http-nio-8090-exec-3] [com.atlassian.ozymandias.SafePluginPointAccess] logThrowable Unable to run plugin code because of 'java.lang.NullPointerException - null'.
    -- referer: http://localhost:8090/pages/resumedraft.action?draftId=327701&draftShareId=17572be0-a57c-4fb1-876c-7f7915524eb6& | url: /rest/api/content/327700 | traceId: b7c3496f3608da46 | userName: admin
   2019-09-04 18:39:02,398 INFO [http-nio-8090-exec-3] [plugins.synchrony.service.SynchronyExternalChangesManager] performExternalChange Started external change for ContentId{id=327700}
   2019-09-04 18:39:02,416 INFO [http-nio-8090-exec-3] [synchrony.service.http.SynchronyRequestExecutor] execute Initiating request PUT http://127.0.0.1:8091/synchrony/v1/data/Synchrony-4917721d-7de9-386c-b41e-f64bd0a9248d/confluence-327700?state-at=@head&state-format=html HTTP/1.1 for 327700
   

   • The odd message is the first one (NPE), seems to be triggered after every page save/publish event

Note:
Those messages seem harmless, but they create unnecessary log noise. This is especially true to the NPE thrown after every page publishing event.