We do another if clause for version 11?

For Debian it looks like:

pg_ctl (PostgreSQL) 11.3 (Debian 11.3-1)

I would make the regex more explicit, to match to the correct version:

re(QStringLiteral("\(PostgreSQL\) ([0-9]+).[0-9]+"))

for Debian it is just:

/usr/lib/postgresql/%1/bin/

You should use the same logic like in postgresSearchPath from DbConfigPostgresql::init to find the old bin dir. I can't see why the old version should be located differently.

please change order to:

1. search for oldBinPath (line 268)
2. test if oldBinPath.isEmpty(line 275)
3. remove old_db_data (l260)

This is more in the sense, that we do not touch anything, if the old Postgres is not installed, as we can't migrate at all.

shouldn't we check if newDbData alread exists before runInitDb? because this is properly an error sate, as newDbData should not exist at this state.

Good catch, let me fix this separately (and propperly).

Thanks.

Tha main difference between this and the lookup in init() is that here we are looking for a specific version of Postgres, while in init() we are looking for the newest one (without knowing what version it is)

really "\\(" ? this is different in different languages, did you tested your regex?

I understand the difference, but in` init() you ONLY check /usr/lib/postgresql/*/bin` and not
/usr/lib64/pgsql/postgresql-*/bin and /usr/lib/pgsql/postgresql-*/bin. I would argue that those dictionaries should be searched in init() too. Because also for other Distributions the new postgres version won't be available in normal search path.Otherwise we will end up in situations, where we fix one place and add a new Distribution style and forget in the other function et visa versa.

The regular expression is "\(", you have to escape the backslash in the C string.

The difference is that on Fedora for instance, the latest version is in /usr/bin, /usr/lib64/pgsql/postgresql-* contains the older versions - in init() we only want the latest version, while here we actively look for an older version.

I will refactor this together with the update to versioned lookup in a next patch.