.\"
.TH PG_UPGRADE 1 "PG_UPGRADE(1)" "14 Jan 2002" "PostgreSQL Client Applications" ""
.SH NAME
pg_upgrade \- upgrading from a previous release without reloading
.SH SYNOPSIS
pg_upgrade [-D \fIdata_dir\fP] -1 | -2
.SH DESCRIPTION
\fBpg_upgrade\fP is a utility for upgrading from a previous PostgreSQL release
without reloading all the data. Not all PostgreSQL releases can use
this utility.  Check the release notes for details about your
version.
.LP
\fBpg_upgrade\fP must be run in two stages.  In phase one you must run
\fBpg_upgrade\fP with your old database installation in place.  In phase two, 
\fBpg_upgrade\fP must be run on a freshly \fBinitdb\fP'ed server.
In both phases, the same newly installed \fBpg_upgrade\fP script must be
used.
.SH Upgrading PostgreSQL with pg_upgrade
.LP
1) Back up your existing data directory, preferably using \fBpg_dumpall.\fP
.LP
2) Copy the program \fIpgsql/contrib/pg_upgrade/pg_upgrade\fP from the current
PostgreSQL distribution somewhere into your path.
.LP
3)  Run phase one of \fBpg_upgrade:\fP
.LP
.B $ pg_upgrade -1
.sp
to collect information about the old database needed for the upgrade.
You may use \fI-D\fP to specify the data directory.  By default it uses
the environment variable \fIPGDATA.\fP
.LP
4) Do:
.LP
.B $ cd pgsql/src
.br
.B $ make install
.sp
to install the PostgreSQL binaries for the new release.
.LP
5)  Do:
.LP
.B $ cd pgsql/contrib/pg_resetxlog
.br
.B $ make install
.sp
to install the \fIpg_resetxlog\fP utility, which is needed during phase
2 of \fBpg_upgrade\fP.
.LP
6) Run initdb to create a new template1 database containing the system
tables for the new release.  Make sure you use settings similar to those
used in your previous version.
.LP
7) Start the new \fIpostmaster.\fP  (Note: it is critical that no users connect
to the server until the upgrade is complete.  You may wish to start the
postmaster without -i or alter pg_hba.conf temporarily.)
.LP
8)  Run phase two of \fBpg_upgrade:\fP
.LP
.B $ pg_upgrade -2
.sp
The program will do some checking to make sure everything is properly
configured, and will then recreate all your databases and tables,
but with no data.  It will then physically move the data files
containing non-system tables and indexes into the proper 
subdirectories.
.LP
9)  Restore your old \fIpostmaster\fP flags or \fIpg_hba.conf\fP if
needed to allow user logins.
.sp
.LP
10)  Carefully examine the contents of the upgraded databases.  If you
detect problems, you'll need to recover by restoring from your full
\fBpg_dumpall\fP backup. You can delete the \fIpg_upgrade_info/\fP directory when you
are satisfied.
.LP
The upgraded databases will be in an un-vacuumed state.  You will
probably want to run a \fIVACUUM ANALYZE\fP before beginning production work.
.SH NOTES
While \fBpg_upgrade\fP is primarly an upgrade tool, it can also be used
as a data recovery tool.
.SH SEE ALSO
initdb(1), postmaster(1), pg_dump(1), pg_dumpall(1), vacuumdb(1)