Ubuntu – What are the differences between gconf and dconf

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I've read a lot of discussion about a new Ubuntu configuration tool: gconf is replaced by dconf.

Why is this change being made? Why is there so much debate about it? Is it too difficult to create a gconf2dconf migration tool?

Best Answer

gconf typically uses an XML backend, while dconf uses its own binary blob. From that change alone you can draw up some points:

Binary read access is far faster than parsing XML
According to dconf's design section, a Gnome login consists of thousands of read operations and only a few writes. To gconf that's thousands of stats, thousands of reads and thousands of parsings. dconf's binary blob would blitz through those without bogging the system down with umpteen thousand IOPs.
XML is more portable
XML is largely human -readable and -editable.
A file-based system can be separated and portioned without much hassle
Corruption of a monolith binary file could mean the whole thing dies. Single file corruption only hurts that segment in gconf.

A lot of the arguments are those levelled for and against the Windows registry.

As I understand it, the interface onto this settings back-end would be the same as gconf: through GSettings. This would allow distributions and users to chose one and switch out if they needed to.

Related Solutions

Ubuntu – the relationship between .gconf, .gnome2, .cache, .local, and other dot-file hierarchies in the home directory

.local, .cache, and .config are part of the FreeDesktop Base Directory Specification. They should not actually be hard-coded but instead use the environment variables (i.e. $XDG_DATA_HOME, $XDG_CACHE_HOME, and $XDG_CONFIG_HOME). There are GLib and Python wrappers for the spec that may be helpful as well. Here's an example in Python:

>>> import xdg.BaseDirectory
>>> print xdg.BaseDirectory.xdg_data_home
/home/andrew/.local/share
>>> print xdg.BaseDirectory.xdg_config_home
/home/andrew/.config
>>> print xdg.BaseDirectory.xdg_cache_home
/home/andrew/.cache

.gnome and .gnome2 are indeed deprecated and should not be used. These were used by libgnome's gnome-config module.

.gconf does indeed contain the settings that gconf-editor accesses as xml files. For instance, compare the output of the following commands:

gconftool -a /desktop/gnome/applications/browser

cat ~/.gconf/desktop/gnome/applications/browser/%gconf.xml

Ubuntu – When to use gconf vs dconf

dconf is a new way for applications to store settings, and it is intended to replace gconf. dconf-editor and gconf-editor are for their respective configuration systems, and they don't talk to each other. At the moment that transition is still a work in progress, so many applications continue to use gconf. In addition, some applications still have settings left over in gconf even though they are using dconf now.

Almost all of the software that is installed by default - everything that comes from GNOME - uses dconf (if anything). Almost everything else that is available uses gconf, though this is of course changing as older software is brought up to date.

So, yes, changing a setting in gconf is likely to do something! If you did a fresh install of Ubuntu 11.10 and didn't migrate your gconf settings, it's likely that everything you see with gconf-editor is being looked at and understood by some current application. If your settings predate 11.10, there may be stuff there that isn't being used.

As a rule of thumb, check dconf first and if what you're looking for isn't there, try gconf.

Best Answer

Related Solutions

Ubuntu – the relationship between .gconf, .gnome2, .cache, .local, and other dot-file hierarchies in the home directory

Ubuntu – When to use gconf vs dconf

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