Recovering databases

What precisely did you update? What are the versions involved? Is this
a package installation (Red Hat/Debian/etc)? or did you build from
source?

The installation is Debian Sarge (3.1). I did a complete update, but
during this I got the information, that Postgresql has to be upgraded
separately - can't remember the exact words.

I did this update and to my suprise it installed a version 7.4. Then i
removed this installation and installed a version 8.1. Afterwards I
cheched to see the packages installed and recognized, that some
7.4-packages still resided om the server.

I there upon (and this is when the big mistake occured) decided to
remove all PG-packages and do a clean install.
The misson succeded but the patient died!

At this moment I got a runing PG but without connecion to the old
databases. The database-files still resides on the server, but I can't
get PG to recognize them.

I think that the PG-installation prior to the mistake was v. 8.0 - I
know for sure that it was newer than 7.x

Regards
Peter


Oliver Elphick skrev:

Locate the main version number that was running with the data. If you
where running 8.0 then 8.1 won't read the data files. A dump and restore
is required to transfer data between releases (but not minor updates).

In the data dir you will find a file named PG_VERSION that contains the
version that created the data files.
The data dir will be the one with base and global dir's and have files
such as pg_hba.conf and postgresql.conf
You can also find the same file inside the base dir folders.

Install the newest update to the version found (if PG_VERSION shows 8.0
then install 8.0.13) and then consider whether you want to dump and
restore to a newer version or to stay with that version.

In that case you should install postgresql-8.0 and
postgresql-client-8.0. That should enable you to get access to your
8.0 database. Unfortunately, they aren't available from the Debian
archive, although they were available in testing for a while before 8.1
came out. They should still exist somewhere on the web.

What puzzles me though is that you are/were running Sarge. The latest
version of postgresql in Sarge is 7.4 (and the current stable release of
Debian is Etch, which has PostgreSQL 8.1). "Doing a complete update"
will presumably have upgraded you to Etch. In Sarge, the postgresql
packages were of version 7.4 but 7.4 did not appear in their names; the
fact that the upgrade to Etch installed *-7.4 packages suggests to me
that you were in fact running 7.4 in Sarge, because the *-7.4 packages
would have been needed to achieve a smooth upgrade. (The postgresql
package in Etch is a transitional package that depends on
postgresql-7.4.)

To check on the version you want, check the contents of the file
PG_VERSION in the database directory. If you are right, it should say
8.0