Upgrade to Tableau Server 2020.4 Fails At Restoring Database With Permission Denied For Table Error

Issue

After fresh installation of Tableau server 2020.4, restoring a backup from Tableau Server 2020.3.0 fails at database step.
Checking the logs shows the following error in databasemaintenance log:

org.postgresql.util.PSQLException: ERROR: permission denied for table <tablename>

Environment

Tableau Server 2020.4.2, 2020.4.3
Windows Server 2012

Resolution

If user created the table mentioned in the error message in Tableau Server repository, remove it from repository and then perform the upgrade.

Since the owner of the table is 'tblwgadmin', in order to connect to repository using this user, please follow below steps to connect to repository and remove the table:

Connection to repository with tblwgadmin user should be performed from loclahost. 'tblwgadmin' does not connect to repository remotely.
In Tableau Server localhost run the following command to retrieve 'tblwgadmin' password:

tsm configuration get -k pgsql.adminpassword

Connect to repository with the following information:

schema: 'workgroup'
user: 'tblwgadmin'
password: use the password from the previous command
Port = 8060

Remove the table mentioned in the error message.
Perform the upgrade

Cause

User created the table mentioned in the error in Tableau Repository.
As of increased security measures in 2020.4, Tableau does not support tables manually created and added to the Tableau database (repository).