DOKK / manpages / debian 13 / postgresql-common / pg_upgradecluster.1.en
PG_UPGRADECLUSTER(1) Debian PostgreSQL infrastructure PG_UPGRADECLUSTER(1)

pg_upgradecluster - upgrade an existing PostgreSQL cluster to a new major version.

pg_upgradecluster [-v newversion] oldversion name [newdatadir]

pg_upgradecluster upgrades an existing PostgreSQL server cluster (i. e. a collection of databases served by a postgres instance) to a new version specified by newversion (default: latest available version). The configuration files of the old version are copied to the new cluster and adjusted for the new version.

By default, pg_dump(1) is used to migrate data and indexes to the new cluster. This is slow, but safe. Upgrade variants based on pg_upgrade(1) can be selected using the --method=upgrade parameter. This is faster, but care must be taken when using it in the context of an operating system upgrade. The sorting order ("collation") used in indexes is determined by libc and libicu, and new versions of these libraries might have a differ ordering, requiring index rebuilds after the upgrade, or acknowledging that the ordering did not change using the ALTER COLLATION REFRESH VERSION command. This step is not automated by pg_upgradecluster.

The cluster of the old version will be configured to use a previously unused port since the upgraded one will use the original port. The old cluster is not automatically removed. After upgrading, please verify that the new cluster indeed works as expected; if so, you should remove the old cluster with pg_dropcluster(8). Please note that the old cluster is set to "manual" startup mode, in order to avoid inadvertently changing it; this means that it will not be started automatically on system boot, and you have to use pg_ctlcluster(8) to start/stop it. See section "STARTUP CONTROL" in pg_createcluster(8) for details.

The newdatadir argument can be used to specify a non-default data directory of the upgraded cluster. It is passed to pg_createcluster. If not specified, this defaults to /var/lib/postgresql/newversion/name.

Set the version to upgrade to (default: latest available).
Check if all packages required for the upgrade are installed.
Proceed with upgrading even when not all packages from the old PostgreSQL version are installed for the new version as well.
Set a custom log file path for the upgraded database cluster.
Set the default locale for the upgraded database cluster. If this option is not specified, the locale is inherited from the old cluster.

When upgrading to PostgreSQL 11 or newer, this option no longer allows switching the encoding of individual databases. (pg_dumpall(1) was changed to retain database encodings.)

Like --locale, but only sets the locale in the specified category.
Specify the upgrade method. dump uses pg_dump(1) and pg_restore(1), upgrade uses pg_upgrade(1). The default is dump.

link and clone are shorthands for -m upgrade --link and -m upgrade --clone, respectively.

In pg_upgrade mode, use hard links instead of copying files to the new cluster. This option is merely passed on to pg_upgrade. See pg_upgrade(1) for details.
In pg_upgrade mode, use efficient file cloning (also known as "reflinks" on some systems) instead of copying files to the new cluster. This option is merely passed on to pg_upgrade. See pg_upgrade(1) for details.
By default, the new cluster is set up to use data page checksums if the old cluster already uses them. Additionally, when using the dump upgrade method, the new cluster will use data page checksums when upgrading to PostgreSQL 18 or later (which enables data page checksums by default).

The --method=dump behavior can explictly be controlled by the --data-checksums and --no-data-checksums options.

In pg_upgrade mode, number of simultaneous processes to use. This option is passed on to pg_upgrade. See pg_upgrade(1) for details. It is also used by the analyze upgrade hook (via the PGJOBS environment variable).
By default, the old cluster is moved to a new port, and the new cluster is moved to the original port so clients will see the upgraded cluster. This option disables that.
Use a different name for the upgraded cluster.
Passed to pg_upgrade.
Database to connect to for maintenance queries. The default is template1.
--[no-]start
Start the new database cluster after upgrading. The default is to start the new cluster if the old cluster was running, or if upgrade hook scripts are present.
If upgrading fails, the newly created cluster is removed. This option disables that.

Some PostgreSQL extensions like PostGIS need metadata in auxiliary tables which must not be upgraded from the old version, but rather initialized for the new version before copying the table data. For this purpose, extensions (as well as administrators, of course) can drop upgrade hook scripts into /etc/postgresql-common/pg_upgradecluster.d/. Script file names must consist entirely of upper and lower case letters, digits, underscores, and hyphens; in particular, dots (i. e. file extensions) are not allowed.

Scripts in that directory will be called with the following arguments:

<old version> <cluster name> <new version> <phase>

Phases:

A virgin cluster of version new version has been created, i. e. this new cluster will already have template1 and postgres, but no user databases. Please note that you should not create tables in this phase, since they will be overwritten by the dump/restore or pg_upgrade operation.
All data from the old version cluster has been dumped/reloaded into the new one. The old cluster still exists, but is not running.

Failing scripts will abort the upgrade. The scripts are called as the user who owns the database.

pg_createcluster(8), pg_dropcluster(8), pg_lsclusters(1), pg_wrapper(1), pg_dump(1), pg_upgrade(1)

Martin Pitt <mpitt@debian.org>, Christoph Berg <myon@debian.org>

2025-05-07 Debian