The forum suggested bumping up the -XMS / -XMX parameters in setenv.sh. In two separate tests (1024m -> 2048m) and (2048m -> 4096m), the result is the same.
After issuing a 'service confluence start' on the sandbox host, the last entry in catalina.out starts with:
2021-03-18 21:07:31,051 WARN [Catalina-utility-1] "[confluence.impl.setup.DefaultBootstrapDatabaseAccessor] readValue Unable to determine ZDU status from database. If you are upgrading from a Confluence version prior to 7.9, this is expected.
org.postgresql.util.PSQLException: ERROR: relation "confzdu" does not exist...
...Security framework of XStream not explicitly initialized, using predefined black list on your own risk."
The back-end database is an AWS RDS instance running PostgreSQL 9.6.
The only occasional log activity is the gc*.current. A netstat shows that 8090 is listening, but a Chrome browser session just spins w/o ever timing out. One of the posts stated that the upgrade takes longer than usual and to "just wait." I waited over 30 minutes before deciding to submit this inquiry.
A rollback to 6.15.2 brings everything back up within 5 minutes.
Thank you.
Karl Romike
SkyTouch Technology
Phoenix Az.