Question: Individual annotations vs One large annotation (conceptual riddle for the interested)
Georg C. F. Greve
greve at kolabsys.com
Wed Sep 28 18:23:32 CEST 2011
There are use cases where XML objects are clearly the better approach, there
are also cases where they are vastly inferior. Typical examples are:
* Anything for email folders:
This will result in a mix of object types within email folders that will
raise the complexity for clients displaying the folders as they can no
longer rely upon the folder type, and non-Kolab clients will more easily
break the configuration.
The alternative results in the next point, and a good chance for data
rot as now the meta data for one particular folder is no longer stored
in that folder.
* More complexity
Where a per folder setting can easily be stored in a shared/private
namespace, and conflict resolution between different settings is easy,
doing the same through XML is more complex.
* Vastly inferior performance
Clients always need to parse everything to retrieve a single setting,
likely across all folders, parsing each object, including filtering
through hundreds of thousands of email messages to make sure
no configuration object is stored among them.
This is in the area of infinitely worse performance in comparison to
annotations, which are a well understood and established mechanism
by now and supported by virtually all the IMAP servers we care about.
That said: There are clearly cases where XML objects are preferable.
In my view, the dividing line runs between transient and permanent
information. Permanent information is everything that is potentially stored
forever, so email, groupware objects, and user specific data, such as a
personal dictionary, even colour sets for commonly used categories across all
object types and the entire data tree.
Transient information is pure configuration data that loses its value with
folders or objects disappearing, so often folder or object specific settings
and meta data, e.g. folder colours, object specific caching or searching
information, even the folder type.
Another deciding bit can be the need to search for information quickly on the
IMAP server without a full cache of everything, but this would have to be a
very strong case to break the logic above, IMHO.
That said: It would have been helpful to get your input on the actual question
discussed in this thread.
Georg C. F. Greve
Chief Executive Officer
Kolab Systems AG
e: greve at kolabsys.com
t: +41 78 904 43 33
pgp: 86574ACA Georg C. F. Greve
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