Comment 1 for bug 1914695

From the strace you posted, it sounds like it's looking up the ndbinfo_version variable, and doesn't like what it gets in return. That sounds like 5.7.33 adds a version requirement that your 5.1.73 server no longer satisfies.

https://launchpadlibrarian.net/520707397/mysql-5.7_5.7.32-0ubuntu0.18.04.1_5.7.33-0ubuntu0.18.04.1.diff.gz

I'm not spotting in the diff any obvious code that is setting a version requirement or otherwise interacting with this variable, though. I wonder if the issue might relate to 5.7.33 expecting to see 'mysql' returned as the first table?

Unfortunately 5.1 is quite past its support date so if the issue is particular to that version I'm not sure there's much we'd do; even 5.7 is rather long in the tooth. However, if you can isolate a change in the above diff that can be traced to the issue, or if you come up with a good mechanism to reproduce the problem, or if you see the issue reproducing with newer server versions, feel free to reopen for us to reconsider.