PostgreSQL: Difference between revisions

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Let the service successfully start once, and then stop it. Upon completion, proceed with the following command, substituting the numbers 15 and 16 with the respective versions you previously used and the more recent one:

<syntaxhighlight>sudo -u postgres pg_upgrade -b "$(nix build --no-link --print-out-paths nixpkgs#postgresql_15.out)/bin" -B /run/current-system/sw/bin -d /var/lib/postgresql/15 -D /var/lib/postgresql/16</syntaxhighlight>~~The~~ [https://nixos.org/manual/nixos/stable/#module-postgresql NixOS manual] also ~~has more detailed~~ information about ~~major~~ upgrades.

<syntaxhighlight>sudo -u postgres pg_upgrade -b "$(nix build --no-link --print-out-paths nixpkgs#postgresql_15.out)/bin" -B /run/current-system/sw/bin -d /var/lib/postgresql/15 -D /var/lib/postgresql/16</syntaxhighlight>

If this fails with the <code>Only the install user can be defined in the new cluster</code> message, you might have some luck using <code>initdb</code> to create the data directory by hand instead of relying on the <code>postgresql</code> systemd service to do that.

Following the example above - upgrading to Postgresql 16 - you'd do:

<syntaxhighlight>rm -rf /var/lib/postgresql/16

sudo -u postgres initdb -D /var/lib/postgresql/16

sudo -u postgres pg_upgrade ...</syntaxhighlight>

Triple check you're not actually <code>rm -rf</code>'ing your actual (previous) database! This is meant to remove only the empty database created by the newer Postgresql version, so that <code>initdb</code> starts with a clean slate.

[https://nixos.org/manual/nixos/stable/#module-postgresql NixOS manual] also contains useful information about this kind of upgrades.

== See also ==

@@ Line 338: / Line 338: @@
 Let the service successfully start once, and then stop it. Upon completion, proceed with the following command, substituting the numbers 15 and 16 with the respective versions you previously used and the more recent one:
-<syntaxhighlight>sudo -u postgres pg_upgrade -b "$(nix build --no-link --print-out-paths nixpkgs#postgresql_15.out)/bin" -B /run/current-system/sw/bin -d /var/lib/postgresql/15 -D /var/lib/postgresql/16</syntaxhighlight>The [https://nixos.org/manual/nixos/stable/#module-postgresql NixOS manual] also has more detailed information about major upgrades.
+<syntaxhighlight>sudo -u postgres pg_upgrade -b "$(nix build --no-link --print-out-paths nixpkgs#postgresql_15.out)/bin" -B /run/current-system/sw/bin -d /var/lib/postgresql/15 -D /var/lib/postgresql/16</syntaxhighlight>
+If this fails with the <code>Only the install user can be defined in the new cluster</code> message, you might have some luck using <code>initdb</code> to create the data directory by hand instead of relying on the <code>postgresql</code> systemd service to do that.
+Following the example above - upgrading to Postgresql 16 - you'd do:
+<syntaxhighlight>rm -rf /var/lib/postgresql/16
+sudo -u postgres initdb -D /var/lib/postgresql/16
+sudo -u postgres pg_upgrade ...</syntaxhighlight>
+Triple check you're not actually <code>rm -rf</code>'ing your actual (previous) database! This is meant to remove only the empty database created by the newer Postgresql version, so that <code>initdb</code> starts with a clean slate.
+[https://nixos.org/manual/nixos/stable/#module-postgresql NixOS manual] also contains useful information about this kind of upgrades.
 == See also ==