id	summary	reporter	owner	description	type	status	priority	milestone	component	version	severity	resolution	keywords	cc
15698	How to upgrade PostgreSQL (and others)	thomas	thomas	"The recent upgrade of PostgreSQL was a major version change. According to the documentation, major version upgrades might introduce incompatibilities - even in the binary format of the data files.

Simply overwriting the installed programs and libraries of PostgreSQL might end up in a unusable database. PostgreSQL has a documentation about upgrading on their website, it is referred to in the blfs page since v14.0.

We had a few comments in the v14.0-ticket (#15631) which is closed in the meanwhile as the version 14 has been worked in: 

> Replying to [comment:2 Douglas R. Reno]:
>> It looks like anyone that uses this will need to run a pg_upgrade prior to restarting postgresql.

>which is, afaik, recommended on every major version change anyhow. Our current instructions are very basic in this regard. To me, it looks like the easiest way to support surviving a format change of the DB is when we do not merge postgres to /usr but install it in /opt/postgresql-x.y.z (and have a symlink /opt/postgresql to it used in $PATH). When installing the new version of postgres, the two versions are available on system and after having run the pg_upgrade and everything works, the previous version in /opt can be removed and the symlink changed to the new version. 

> Same for /srv/pgsql/data which than should be /srv/pgsql/data-x.y.z.

This ticket is to continue the discussion on how to perform a a upgrade of existing installations. The question is

1. Do we care about upgrading existing installations at all or is a pointer to pgsql's documentation enough
1. Is the way mentioned above the correct way to provide upgradable program/library installation as a prerequisite to use `pg_upgrade`
1. is there a way to use the compiled but not yet installed binaries to upgrade the old data files (in which case the installation path of Postgres could remain being /usr)
1. How to handle upgrades on other DBs like MariaDB
"	enhancement	closed	normal	11.1	BOOK	git	medium	fixed	postgresql