How do ghost accounts get re-associated with the proper local account?

[warecm43]

I had a user in our confluence system and then they left the company. We removed his AD account and created a local account to keep track of the documentation he had submitted. He was rehired and during setup the local account was apparently removed before the AD account was added back. He has since left again. We removed the AD account and added a local account back with the same credential as before, however, we can't see any documentation related to his prior time. We have tracked down the documents and they are now tied to the following account: user-6591a. How can I change the account information back to the proper user id? I have access to the psql backend database if required to make this work.

The information given by the AI Support, gave a psql command to search for the user keys for both the ghost and local account, but it only finds the new local account, not the ghost account.  

Does anyone have any experience is correcting this situation?

If I run the following command:  select user_key, username from user_mapping where username like '%user%';  

nothing is found even though the system shows the 'user-6591a' as tied to documents previously written by the user with the new local account id.

[Radwan Almsora]

To re-associate the orphaned documentation with the user’s new local or AD account, you must connect directly to your psql database. The problem occurs because Confluence links content to users via user_key, not usernames. When you recreated the local account, it was assigned a new user_key, while the documents remained tied to the ghost account's user_key (such as user-6591a).

I belive this was answered here: 

Find Unknown Users and pages created by them in Confluence Data Center

How to obtain a list of all pages, their authors, and related information from the Confluence database