Subject: Re: [PATCH] guix gc: Add '--vacuum-store'.

From: Liliana Marie Prikler <[email-masked]>
Date: Thu, 20 Oct 2022 20:51:04 +0200

Am Mittwoch, dem 19.10.2022 um 12:26 +0300 schrieb Efraim Flashner:
> * guix/scripts/gc.scm (show-help, %options): Add '--vacuum-store'.
> * guix/store/database.scm (vacuum-database): New procedure.
> * doc/guix.texi (Invoking guix gc): Document the option.
> ---
>  doc/guix.texi           | 11 +++++++++++
>  guix/scripts/gc.scm     | 11 +++++++++++
>  guix/store/database.scm |  9 ++++++++-
>  3 files changed, 30 insertions(+), 1 deletion(-)
> 
> diff --git a/doc/guix.texi b/doc/guix.texi
> index 3bf2dee752..89fd04415a 100644
> --- a/doc/guix.texi
> +++ b/doc/guix.texi
> @@ -4531,6 +4531,17 @@ Invoking guix gc
>  this option is primarily useful when the daemon was running with
>  @option{--disable-deduplication}.
>  
> +@item --vacuum-store
> +@cindex vacuum the store database
> +@comment Avoid words like 'repair,' 'compress,' and 'optimize.'
> +Guix uses an sqlite database to keep track of the items in
> (@pxref{The Store}).
> +Overtime it is possible that the database may grow to a large size
> and become
> +fragmented.  As a result, one may wish to clear the freed space and
> join the
> +partially used pages in the database left behind from removed
> packages or after
> +running the garbage collector.  Running @command{sudo guix gc --
> vacuum-store}
> +will lock the database and @code{VACUUM} the store, defragmenting
> the database
> +and purging freed pages, unlocking the database when it finishes..
You're using vacuum-store here...

>  @end table
>  
>  @node Invoking guix pull
> diff --git a/guix/scripts/gc.scm b/guix/scripts/gc.scm
> index 65cd4bdf8b..5e775c5cdb 100644
> --- a/guix/scripts/gc.scm
> +++ b/guix/scripts/gc.scm
> @@ -1,5 +1,6 @@
>  ;;; GNU Guix --- Functional package management for GNU
>  ;;; Copyright © 2012-2013, 2015-2020, 2022 Ludovic Courtès
> <[email-masked]>
> +;;; Copyright © 2022 Efraim Flashner <[email-masked]>
>  ;;;
>  ;;; This file is part of GNU Guix.
>  ;;;
> @@ -27,6 +28,7 @@ (define-module (guix scripts gc)
>                                  generation-number)
>    #:autoload   (guix scripts package) (delete-generations)
>    #:autoload   (gnu home) (home-generation-base)
> +  #:autoload   (guix store database) (vacuum-database)
>    #:use-module (ice-9 match)
>    #:use-module (ice-9 regex)
>    #:use-module (srfi srfi-1)
> @@ -86,6 +88,10 @@ (define (show-help)
>    (display (G_ "
>        --clear-failures   remove PATHS from the set of cached
> failures"))
>    (newline)
> +  (display (G_ "
> +      --vacuum-database  repack the sqlite database tracking the
> store
> +                         using less space"))
> +  (newline)
>    (display (G_ "
>    -h, --help             display this help and exit"))
>    (display (G_ "
> @@ -131,6 +137,11 @@ (define %options
>                  (lambda args
>                    (show-version-and-exit "guix gc")))
>  
> +        (option '("vacuum-database") #f #f
> +                (lambda args
> +                  (vacuum-database)
> +                  (exit 0)))
> +
>          (option '(#\C "collect-garbage") #f #t
>                  (lambda (opt name arg result)
>                    (let ((result (alist-cons 'action 'collect-garbage
> diff --git a/guix/store/database.scm b/guix/store/database.scm
> index 8d08def833..e664015673 100644
> --- a/guix/store/database.scm
> +++ b/guix/store/database.scm
> @@ -2,6 +2,7 @@
>  ;;; Copyright © 2017, 2019 Caleb Ristvedt <[email-masked]>
>  ;;; Copyright © 2018, 2020, 2021 Ludovic Courtès <[email-masked]>
>  ;;; Copyright © 2020 Jan (janneke) Nieuwenhuizen <[email-masked]>
> +;;; Copyright © 2022 Efraim Flashner <[email-masked]>
>  ;;;
>  ;;; This file is part of GNU Guix.
>  ;;;
> @@ -45,7 +46,8 @@ (define-module (guix store database)
>              sqlite-register
>              register-items
>              %epoch
> -            reset-timestamps))
> +            reset-timestamps
> +            vacuum-database))
>  
>  ;;; Code for working with the store database directly.
>  
> @@ -438,3 +440,8 @@ (define* (register-items db items
>                      (register db item)
>                      (report))
>                    items)))))
> +
> +(define (vacuum-database)
> +  (let ((db (sqlite-open (store-database-file))))
> +    (sqlite-exec db "VACUUM;")
> +    (sqlite-close db)))
... but vacuum-database here.

Since the database is just a part of the store, I think making it
"vacuum-database" everywhere ought to make it both more consistent and
more correct.

Cheers