Upgrading to 7.3 from 7.2

                             If You Are Upgrading

The internal data storage format changes with new releases of PostgreSQL.
Therefore, if you are upgrading an existing installation that does not have a
version number "7.3.x", you must back up and restore your data as shown here.
These instructions assume that your existing installation is under the "/usr/
local/pgsql" directory, and that the data area is in "/usr/local/pgsql/data".
Substitute your paths appropriately.

   1. Make sure that your database is not updated during or after the backup.
      This does not affect the integrity of the backup, but the changed data
      would of course not be included. If necessary, edit the permissions in
      the file "/usr/local/pgsql/data/pg_hba.conf" (or equivalent) to disallow
      access from everyone except you.

   2. To back up your database installation, type:

        pg_dumpall > outputfile

      If you need to preserve OIDs (such as when using them as foreign keys),
      then use the "-o" option when running "pg_dumpall".
      "pg_dumpall" does not save large objects. Check the Administrator's Guide
      if you need to do this.
      To make the backup, you can use the "pg_dumpall" command from the version
      you are currently running. For best results, however, try to use the
      "pg_dumpall" command from PostgreSQL 7.3, since this version contains
      bug fixes and improvements over older versions. While this advice might
      seem idiosyncratic since you haven't installed the new version yet, it is
      advisable to follow it if you plan to install the new version in parallel
      with the old version. In that case you can complete the installation
      normally and transfer the data later. This will also decrease the
      downtime.

   3. If you are installing the new version at the same location as the old one
      then shut down the old server, at the latest before you install the new
      files:

        kill -INT `cat /usr/local/pgsql/data/postmaster.pid`

      Versions prior to 7.0 do not have this "postmaster.pid" file. If you are
      using such a version you must find out the process id of the server
      yourself, for example by typing "ps ax | grep postmaster", and supply it
      to the "kill" command.
      On systems that have PostgreSQL started at boot time, there is probably a
      start-up file that will accomplish the same thing. For example, on a Red
      Hat Linux system one might find that

        /etc/rc.d/init.d/postgresql stop

      works. Another possibility is "pg_ctl stop".

   4. If you are installing in the same place as the old version then it is
      also a good idea to move the old installation out of the way, in case you
      have trouble and need to revert to it. Use a command like this:

        mv /usr/local/pgsql /usr/local/pgsql.old

After you have installed PostgreSQL 7.3, create a new database directory and
start the new server. Remember that you must execute these commands while
logged in to the special database user account (which you already have if you
are upgrading).

  /usr/local/pgsql/bin/initdb -D /usr/local/pgsql/data
  /usr/local/pgsql/bin/postmaster -D /usr/local/pgsql/data

Finally, restore your data with

  /usr/local/pgsql/bin/psql -d template1 -f outputfile

using the *new* psql.
These topics are discussed at length in the Administrator's Guide, which you
are encouraged to read in any case.