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99 lines
3.6 KiB
Groff
99 lines
3.6 KiB
Groff
.\"
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.TH PG_UPGRADE 1 "PG_UPGRADE(1)" "14 Jan 2002" "PostgreSQL Client Applications" ""
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.SH NAME
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pg_upgrade \- upgrading from a previous release without reloading
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.SH SYNOPSIS
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pg_upgrade [-D \fIdata_dir\fP] -1 | -2
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.SH DESCRIPTION
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\fBpg_upgrade\fP is a utility for upgrading from a previous PostgreSQL
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release without reloading all the data. It can also be used as a data
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recovery tool.
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.LP
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\fBpg_upgrade\fP must be run in two stages. In phase one you must run
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\fBpg_upgrade\fP with your old database installation in place. In phase
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two, \fBpg_upgrade\fP must be run on a freshly \fBinitdb\fP'ed server.
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In both phases, the same newly installed \fBpg_upgrade\fP script must be
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used.
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.SH Upgrading PostgreSQL with pg_upgrade
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.LP
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1) Back up your existing data directory, preferably using
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\fBpg_dumpall.\fP
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.LP
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2) Copy the program \fIpgsql/contrib/pg_upgrade/pg_upgrade\fP from the
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current PostgreSQL distribution somewhere into your path.
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.LP
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3) Run phase one of \fBpg_upgrade:\fP
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.LP
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.B $ pg_upgrade -1
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.sp
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to collect information about the old database needed for the upgrade.
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You may use \fI-D\fP to specify the data directory. By default it uses
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the environment variable \fIPGDATA.\fP
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.LP
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4) Do:
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.LP
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.B $ cd pgsql/src
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.br
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.B $ make install
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.sp
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to install the PostgreSQL binaries for the new release.
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.LP
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5) Do:
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.LP
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.B $ cd pgsql/contrib/pg_resetxlog
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.br
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.B $ make install
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.sp
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to install the \fIpg_resetxlog\fP utility, which is needed during phase
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2 of \fBpg_upgrade\fP.
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.LP
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6) Run initdb to create a new template1 database containing the system
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tables for the new release. Make sure you use settings similar to those
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used in your previous version.
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.LP
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7) Start the new \fIpostmaster.\fP (Note: it is critical that no users
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connect to the server until the upgrade is complete. You may wish to
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start the postmaster without -i or alter pg_hba.conf temporarily.)
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.LP
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8) Run phase two of \fBpg_upgrade:\fP
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.LP
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.B $ pg_upgrade -2
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.sp
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The program will do some checking to make sure everything is properly
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configured, and will then recreate all your databases and tables,
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but with no data. It will then physically move the data files
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containing non-system tables and indexes into the proper
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subdirectories.
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.LP
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9) Restore your old \fIpostmaster\fP flags or \fIpg_hba.conf\fP if
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needed to allow user logins.
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.sp
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.LP
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10) Carefully examine the contents of the upgraded databases. If you
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detect problems, you'll need to recover by restoring from your full
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\fBpg_dumpall\fP backup. You can delete the \fIpg_upgrade_info/\fP
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directory when you are satisfied.
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.LP
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The upgraded databases will be in an un-vacuumed state. You will
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probably want to run a \fIVACUUM ANALYZE\fP before beginning production
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work.
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.SH NOTES
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While \fBpg_upgrade\fP is primarly an upgrade tool, it can also be used
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for data recovery. During phase 1, \fBpg_upgrade\fP creates database
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name / oid and database name / table name / oid mapping files in
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\fIpg_upgrade_info/.\fP These files are tab-delimited. If your system is
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too damaged, you may need to manually pull this information out of
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\fBpg_database\fP and \fBpg_class\fP and create the files manually.
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(Keep in mind most tables have \fBpg_toast_OID\fP and
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\fBpg_toast_OID_idx\fP files that store very long values. These must be
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recorded as well.) It also creates a schema-only \fBpg_dumpall.\fP In a
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damaged installation, you may be able to make one of these from a recent
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full \fBpg_dumpall.\fP
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.LP
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Phase 2 rebuilds each database with the schema from the old
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installation. It then moves the physical data files from the old
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installation and makes some modifications so the old data files work
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properly in the new installation.
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.SH SEE ALSO
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initdb(1), postmaster(1), pg_dump(1), pg_dumpall(1), vacuumdb(1)
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