Re: Upgrading side by side in Gentoo

Ok, I work at a hosting company that runs Gentoo as it's main host
operating system so here's the skivvy on the current status of
PostgreSQL under portage.

Up until just a few months ago the needed packages were called libpq
and postgresql (go figure).  These were *not* slotted and so did not
support having multiple versions of Postgres installed from portage
simultaneously.  For 8.2, 8.2, and 8.3 those packages go up to 8.1.11,
8.2.7 and 8.3.1, respectively.

So, recently the Postgres package maintainer decided to remedy that
situation by changing the ebuild format to a slotted format to allow
(supposedly) multiple versions to be installed side-by-side, these are
called postgresql-base and postgresql-server and start with 8.1.11,
8.2.10, and 8.3.4.   Of course, when this change was made this created
much havoc in our install scripts here at work as the two package
formats are incompatible (meaning you can't both libpq/postgresql and
postgresql-base/postgresql-server installed at the same time) and they
even changed the names of the init scripts and /etc/conf.d/ files.

In addition, the first time I had the, um, opportunity to install the
slotted versions of 8.2 and 8.3 side by side it didn't work out too
well.  They both installed fine but I ran into problems when I needed
to emerge postgis linked against 8.2:  the packages install wrapper
scripts for the client programs that find the latest available version
on the system, including pg_config.  In the end I had to completely
unmerge 8.3 in order to get postgis to link against 8.2.  For simple
upgrades this kind of thing won't be an issue.

So, Andrus, if you want to upgrade to the latest version of 8.3 using
portage you're going to have to unmerge 8.1 (both libpq and
postgreseql) in addition to all of the steps you've already listed
which are pretty standard.  Given that, if something goes wrong you'll
need to include umerging 8.3 (postgresql-base and postgresql-server)
and re-emerging 8.1.

P.S.  To whomever said that Gentoo for for single users running
cutting edge software, poppycock.  Any self-respecting company running
Gentoo should be maintaining their own portage build servers just as a
Debian based company would maintain their own build servers for apt or
RedHat/CentOS for rpm/yum.

Erik Jones, Database Administrator
Engine Yard
Support, Scalability, Reliability
866.518.9273 x 260
Location: US/Pacific
IRC: mage2k