First of all: Use my suggestions and any other information in this note at your own risk. PostgreSQL is a serious DBMS (though its core developers sometimes don’t even seem to recognize this themselves) and you should be careful before taking any steps that could affect your important data.
Between the muck-ups of Red Hat and PostgreSQL, you are likely to face some nastiness if you are upgrading to RH9. First of all, be sure to
pg_dumpall to back up your current instances before the upgrade. The upgrade will replace the PG 7.2 RPMs with 7.3 RPMs, and these are incompatible versions, so you will have to blow away the current instances, using something such as:
rm -rf /var/lib/pgsql/data/* rm /var/lib/pgsql/initdb.i18n
Then you can start the PG 7.3 using
/etc/init.d/postgresql start and restore using
pg_restore. But even this may not be straightforward. As it says in /usr/share/doc/postgresql-7.3.2/README.rpm-dist:
The 7.2 to 7.3 migration can be quite difficult, even to the point of requiring hand-editing of the dumpfile.
This whole situation is a mess. See this posting for an exchange that gives an example of the problems this is causing for users. I hope a little forewarning helps minimize the problems you face upon migration.