In <list-7574125@2rosenthals.com>, on 08/01/23
    at 01:21 PM, "Massimo S." <ecs-isp@2rosenthals.com> said:

about 5.6.51 it don't start here
i'm going to open a ticket

A few comments on ticket #777.

I got sufficiently curious to do some local testing to see what failures
might occur using my databases.  I was able to trigger some failures, but
not your failure.

I suspect the mysql_upgrade is sensitive to the data being upgraded and
v5.1 to v5.6 is a big jump, so let's backup and locate the source of the
failure.

Populate your v5.6 data directory tree with just the mysql subdirectory.
Run mysqld --console to make sure the server will start.  Then run
mysql-upgrade.  If this works, copy another v5.1 database to the v5.6 data
directory and run mysql_upgrade --force.  Repeat this until you find which
database is the problem.

FWIW, one of the failures I got was:

2023-08-07 23:09:11 6198 [ERROR] Incorrect definition of table mysql.proc:
expected column 'comment' at position 15 to have type text, found type
char(64).

followed by a LIBC PANIC.

I have to assume that I ran into this when I upgrade these databases to
v5.6, but I did not keep notes of what I did the get past it.  Most
likely, I used mysql_install_db.pl

to populate the mysql system tables and
used mysql_upgrade for the rest.

It's getting late here, so I'm done for now.  Tomorrow, I will do some
mysqlcheck runs to make sure the v5.1 databases have no issues.

If we cannot fix your v5.1 databases to work with mysql, the alternative
will be to dump and reload.  I've used this method in the past when the
upgrade will not cooperate.

Steven