`command-not-found` unable to open database

I am on NixOS and command-not-found feature is no longer working.

I don’t have any configuration for it in configuration.nix, it should enable by default.

What should I do to fix it?

$ command-not-found
DBI connect('dbname=/nix/var/nix/profiles/per-user/root/channels/nixos/programs.sqlite','',...) failed: unable to open database file at /run/current-system/sw/bin/command-not-found line 13.
cannot open database `/nix/var/nix/profiles/per-user/root/channels/nixos/programs.sqlite' at /run/current-system/sw/bin/command-not-found line 13.
1 Like

I’ve had that issue as well. What you need to make sure is that root's channels include a channel named nixos. You can point it to a nixos-unstable.

If all of your channels are deleted (use nix-channel --delete and nix-channel --list to view them), you can add the unstable channel and name it unstable with:

nix-channel --add https://nixos.org/channels/nixos-unstable nixos
1 Like

Too bad this doesn’t work, I already have nixos-unstable as nixos (for root).

Any idea?

[root@earth:~]# nix-channel --list
nixos https://nixos.org/channels/nixpkgs-unstable

[root@earth:~]# command-not-found 
DBI connect('dbname=/nix/var/nix/profiles/per-user/root/channels/nixos/programs.sqlite','',...) failed: unable to open database file at /run/current-system/sw/bin/command-not-found line 13.
cannot open database `/nix/var/nix/profiles/per-user/root/channels/nixos/programs.sqlite' at /run/current-system/sw/bin/command-not-found line 13.

[wizzup@ ~]$ nix-channel --list
[wizzup@ ~]$ command-not-found 
DBI connect('dbname=/nix/var/nix/profiles/per-user/root/channels/nixos/programs.sqlite','',...) failed: unable to open database file at /run/current-system/sw/bin/command-not-found line 13.
cannot open database `/nix/var/nix/profiles/per-user/root/channels/nixos/programs.sqlite' at /run/current-system/sw/bin/command-not-found line 13.

The programs.sqlite is only generated for the nixos- prefixed channels.

As root, run:

nix-channel --add https://nixos.org/channels/nixos-unstable nixos
nix-channel --update
2 Likes

This works! Do I need to do this command sequences every time after nixos-rebuild switch?

[root@earth:~]# nix-channel --add https://nixos.org/channels/nixos-unstable nixos

[root@earth:~]# nix-channel --list
nixos https://nixos.org/channels/nixos-unstable

[root@earth:~]# nix-channel --update
unpacking channels...

[root@earth:~]# command-not-found hello
The program ‘hello’ is currently not installed. It is provided by
several packages. You can install it by typing one of the following:
  nix-env -iA nixos.hello
  nix-env -iA nixos.mbedtls
  nix-env -iA nixos.perkeep

It should be fine now.

The issue was that the system was configured with nixpgs- unstable. Small but important difference :slight_smile:

The nixos- channels are produced by Hydra - Project nixos
The nixpkgs- channels are produced by https://hydra.nixos.org/project/nixpkgs

Both have different release scripts and criteria for advancement.

2 Likes

I’m seeing this in 21.11, and none of the above suggestions appear to work for me.

My root user appears to have the correct channel:

$ id
uid=0(root) gid=0(root) groups=0(root)
$ nix-channel --list
nixos https://nixos.org/channels/nixos-21.11

But command-not-found still can’t find the database:

$ command-not-found
DBI connect('dbname=/nix/var/nix/profiles/per-user/root/channels/nixos/programs.sqlite','',...) failed: unable to open database file at /run/current-system/sw/bin/command-not-found line 13.
cannot open database `/nix/var/nix/profiles/per-user/root/channels/nixos/programs.sqlite' at /run/current-system/sw/bin/command-not-found line 13.

This error message seems reasonable, since the programs.sqlite database really doesn’t exist:

$ ls -lah /nix/var/nix/profiles/per-user/root/channels/nixos/programs.sqlite
ls: cannot access '/nix/var/nix/profiles/per-user/root/channels/nixos/programs.sqlite': No such file or directory
$ ls -lah /nix/var/nix/profiles/per-user/root/channels/nixos/
total 88K
dr-xr-xr-x  8 root root 4.0K Jan  1  1970 .
dr-xr-xr-x  3 root root 4.0K Jan  1  1970 ..
-r--r--r--  1 root root 4.9K Jan  1  1970 CONTRIBUTING.md
-r--r--r--  1 root root 1.1K Jan  1  1970 COPYING
-r--r--r--  1 root root  971 Jan  1  1970 default.nix
dr-xr-xr-x 11 root root 4.0K Jan  1  1970 doc
-r--r--r--  1 root root 2.3K Jan  1  1970 .editorconfig
-r--r--r--  1 root root 3.3K Jan  1  1970 flake.nix
-r--r--r--  1 root root  598 Jan  1  1970 .gitattributes
dr-xr-xr-x  4 root root 4.0K Jan  1  1970 .github
-r--r--r--  1 root root  344 Jan  1  1970 .gitignore
-r--r--r--  1 root root   40 Jan  1  1970 .git-revision
dr-xr-xr-x  4 root root 4.0K Jan  1  1970 lib
dr-xr-xr-x  3 root root 4.0K Jan  1  1970 maintainers
dr-xr-xr-x  7 root root 4.0K Jan  1  1970 nixos
lrwxrwxrwx  1 root root    1 Jan  1  1970 nixpkgs -> .
dr-xr-xr-x 18 root root 4.0K Jan  1  1970 pkgs
-r--r--r--  1 root root 5.8K Jan  1  1970 README.md
-r--r--r--  1 root root   20 Jan  1  1970 svn-revision
-r--r--r--  1 root root    5 Jan  1  1970 .version
-r--r--r--  1 root root   19 Jan  1  1970 .version-suffix

Any idea what could be going on here?

edit: I should add my nixos commit:

$ cat /nix/var/nix/profiles/per-user/root/channels/nixos/.git-revision 
1bd4bbd49bef217a3d1adea43498270d6e779d65

Huh, apparently running sudo nix-channel --update got me the programs.sqlite database.

$ sudo nix-channel --update
$ cat /nix/var/nix/profiles/per-user/root/channels/nixos/.git-revision 
573095944e7c1d58d30fc679c81af63668b54056
$ ls -l /nix/var/nix/profiles/per-user/root/channels/nixos/programs.sqlite 
-r--r--r-- 1 root root 10076160 Jan  1  1970 /nix/var/nix/profiles/per-user/root/channels/nixos/programs.sqlite

So now the question is, is running nix-channel --update at least once required? Or are there just certain channel commits that don’t have a programs.sqlite generated?

In case you are using Nix Flakes, then you can use nix-index for the command-not-found functionality. If you use home-manager, add this to your home.nix:

programs.nix-index =
{
  enable = true;
  enable<SHELL>Integration = true;
};
2 Likes

I presume one still have to play around NIX_PATH: Make use of Nix flake registry instead of channel · Issue #167 · bennofs/nix-index · GitHub

1 Like

Yeah you’re right, I use autoGenFromInputs module from flake-utils-plus to auto-generate NIX_PATH from Flake inputs, so everything works fine

1 Like
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