Sync Database

Pacman downloads remote database files, that it uses to synchronize its local state with a remote Binary Repository and to figure out which packages to download and upgrade.

The sync database files are tar files, that may be gzip, bzip2, xz or zstd compressed. Two types of files are supported: Default sync databases (suffixed with .db) and files databases (suffixed with .files).

Note

There is only ever one version of a given package present in a repository. Although the Binary Repository may contain several versions of a package, the sync database ensures that only up to one is ever exposed to the user.

Default Database

In the default database each package in its current version is represented by a directory and a desc file:

.
├── package-1.0.0-1
│   └── desc
[..]

A desc file carries identifiers and their values, which describe a package (see Desc).

Files Database

In the files database each package in its current version is represented by a directory containing a desc and a files file:

.
├── package-1.0.0-1
│   ├── desc
│   └── files
[..]

The desc file is the same as in the default database, while the files file represents the list of files of a given package (see Files).

Desc

Repository sync databases contain per-package desc files, that carry identifiers and their values, which serve to describe a package.

Identifiers are composed of a string in all capital letters [A-Z] with a leading and a trailing % character. All identifiers as well as values are provided on a per-line basis in a desc file, leaving an empty line between each identifier/value pair.

Identifiers may be required or optional. As requirements change over time and identifiers and their values may be added or removed, the desc files are distinguished using the below versioning.

Desc v1

  • %ARCH% (required): The CPU architecture of the package (one line below the identifier)

  • %BACKUP%: A list of package files to be backed up by the package manager (one file per line below the identifier)

  • %BASE% (required): The pkgbase (see split package) of a package (one line below the identifier)

  • %BUILDDATE% (required): The time - in seconds since the epoch - when the package has been built (one line below the identifier)

  • %CHECKDEPENDS%: A list of package names required when running the check() package function (one name per line below the identifier)

  • %CONFLICTS%: A list of package names that conflict with a package (one name per line below the identifier)

  • %CSIZE% (required): The size - in Bytes - of the compressed package (one line below the identifier)

  • %DEPENDS%: A list of package names that a package depends on (one name per line below the identifier)

  • %DESC% (required): The description of a package (one line below the identifier)

  • %FILENAME% (required): The filename of a package file (one line below the identifier)

  • %GROUPS%: A list of package group names that a package belongs to (one name per line below the identifier)

  • %ISIZE% (required): The size - in Bytes - of the package when installed (one line below the identifier)

  • %LICENSE% (required): A list of license names that the files of a package are licensed under (one name per line below the identifier)

  • %MAKEDEPENDS%: A list of package names required when running the prepare() and/ or build() package function (one name per line below the identifier)

  • %MD5SUM% (required): The md5 checksum of the package file (one line below the identifier)

  • %NAME% (required): The name of the package (one line below the identifier)

  • %OPTDEPENDS%: A list of package names that can be used optionally to extend a package’s functionality (one name per line below the identifier)

  • %PACKAGER% (required): The UID (name and e-mail address) of the packager who created a package (one line below the identifier)

  • %PGPSIG% (required): The base64 encoded PGP signature of a package (one line below the identifier)

  • %PROVIDES%: A list of package names that a package provides (one name per line below the identifier)

  • %REPLACES%: A list of package names that a package replaces (one name per line below the identifier)

  • %SHA256SUM% (required): The sha256 checksum of the package file (one line below the identifier)

  • %URL% (required): The URL of the package (one line below the identifier)

  • %VERSION% (required): The version string of the package (one line below the identifier)

Desc v2

This version removes the %MD5SUM% field as this hashing algorithm is unsafe. Furthermore the %PGPSIG% field has been made optional to lower the size of the created Sync Database files.

  • %ARCH% (required): The CPU architecture of the package (one line below the identifier)

  • %BACKUP%: A list of package files to be backed up by the package manager (one file per line below the identifier)

  • %BASE% (required): The pkgbase (see split package) of a package (one line below the identifier)

  • %BUILDDATE% (required): The time - in seconds since the epoch - when the package has been built (one line below the identifier)

  • %CHECKDEPENDS%: A list of package names required when running the check() package function (one name per line below the identifier)

  • %CONFLICTS%: A list of package names that conflict with a package (one name per line below the identifier)

  • %CSIZE% (required): The size - in Bytes - of the compressed package (one line below the identifier)

  • %DEPENDS%: A list of package names that a package depends on (one name per line below the identifier)

  • %DESC% (required): The description of a package (one line below the identifier)

  • %FILENAME% (required): The filename of a package file (one line below the identifier)

  • %GROUPS%: A list of package group names that a package belongs to (one name per line below the identifier)

  • %ISIZE% (required): The size - in Bytes - of the package when installed (one line below the identifier)

  • %LICENSE% (required): A list of license names that the files of a package are licensed under (one name per line below the identifier)

  • %MAKEDEPENDS%: A list of package names required when running the prepare() and/ or build() package function (one name per line below the identifier)

  • %NAME% (required): The name of the package (one line below the identifier)

  • %OPTDEPENDS%: A list of package names that can be used optionally to extend a package’s functionality (one name per line below the identifier)

  • %PACKAGER% (required): The UID (name and e-mail address) of the packager who created a package (one line below the identifier)

  • %PGPSIG%: The base64 encoded PGP signature of a package (one line below the identifier)

  • %PROVIDES%: A list of package names that a package provides (one name per line below the identifier)

  • %REPLACES%: A list of package names that a package replaces (one name per line below the identifier)

  • %SHA256SUM% (required): The sha256 checksum of the package file (one line below the identifier)

  • %URL% (required): The URL of the package (one line below the identifier)

  • %VERSION% (required): The version string of the package (one line below the identifier)

Files

The files repository sync databases contain per-package files files, that carry identifiers and their values, which serve to describe the contents of a package.

Identifiers are composed of a string in all capital letters [A-Z] with a leading and a trailing % character. All identifiers as well as values are provided on a per-line basis in a files file, leaving an empty line between each identifier/value pair.

Identifiers may be required or optional. As requirements change over time and identifiers and their values may be added or removed, the files files are distinguished using the below versioning.

Files v1

  • %FILES% (required): A list of files and directories contained in a package (one file per line below the identifier)