Upgrade to mysql 5.7 and now Confluence 7.31 can no longer connect

[Michael Warchut]

Good morning

I made a clone of our production confluence server to test upgrading mysql up to 5.7 and ultimately to 8.0.  I started upgrading the version of 5.6 to the latest 5.6 and then running mysql_upgrade with no issue.  I then started confluence and was able to start and login to it.  I shutdown confluence and mysql and upgraded it to the latest 5.7 GA release. Mysql starts ok and the DB is available by way of the mysql client.  But when I go to start confluence I get very vague errors, nothing of real help.  I've scoured the internet and so far have not found a potential solution.  Errors below.  I even updated the jdbc driver to mysql-connector-java-5.1.49 from the lesser version of mysql-connector-java-5.1.24 in case that was an issue.  Suggestions welcome.

2021-01-28 16:36:09,729 INFO [Catalina-utility-1] [springframework.web.context.ContextLoader] initWebApplicationCo
ntext Root WebApplicationContext initialized in 12456 ms
2021-01-28 16:36:22,434 ERROR [Catalina-utility-1] [confluence.impl.health.DefaultHealthCheckRunner] logEvent Data
base connection failed
2021-01-28 16:36:22,438 ERROR [Catalina-utility-1] [confluence.impl.health.DefaultHealthCheckRunner] logEvent Conf
luence failed to establish a connection to your database.
This could be because:
- Your database isn't running
- The configuration of your confluence.cfg.xml file is incorrect (user, password, or database URL etc.)
- There is a network issue between Confluence and your database (e.g. firewall, database doesn't allow rem
ote access etc.)

There are several other solutions you can try, review our documentation and see what works for you.

2021-01-28 16:36:26,501 WARN [Catalina-utility-1] [atlassian.confluence.setup.DefaultBootstrapManager] getDatabase
BuildNumber Unable to determine build number from database. If you are upgrading from a Confluence version prior t
o 2.3, this is expected: Could not create connection to database server. Attempted reconnect 3 times. Giving up.

[Michael Warchut]

So I did a ton of digging today and figured it out.  It was a behaviour change in mysql and some bogus data in the user table of mysql.  I inherited this system from another company so this is my first deep dive into it.  The user table had two confluence accounts, one with localhost as the host and the other with 127.0.0.1 as the host with two different passwords. Obviously 5.6 matched the 'localhost' account but 5.7 matched the latter, or errored because of the potential conflict.  I removed the @127.0.0.1 account and now it logs in.