[netcdf-java] Persisting a NetcdfDatasetCache

[Nils Hoffmann]

Hi Jon and also to the list,
Jon Blower wrote:
> Hi Nick and John (and list),
> 
> I was about to write pretty much exactly what Nick just wrote - the
> serialization would be for short-term storage so I don't think there's
> a problem there (although I guess some people might try to misuse the
> serialization capability if it were provided).
> 
> My _guess_ is that there is no need to keep open file handles and the
> overhead of opening a NetcdfDataset is mostly in the reading of the
> metadata into the relevant structures (Attributes, Axes etc),
> particularly if the dataset is an aggregation (actually it was
> aggregations that I had in mind when I suggested the persistent store
> in the first place).  However, some testing would be needed of course
> - I don't really know.
> 
> Maybe the metadata could be stored in some other way than
> serialization. We have done some analogous experiments with trying to
> use a relational database to store metadata but the problem is that
> the database gets complicated when you start dealing with projections
> and the like.  Object-relational mapping could help to manage the
> complexity but this won't be trivial to code (e.g. could use Hibernate
> over an embedded database like H2).

Maybe instead of going through the hassle of setting up an OR mapping,
you might want to have a look at http://www.db4o.com/, which is an 
object database also for Java. It does not require class annotations
or xml descriptions of mappings so it is rather quick to set up, 
although I must admit that I haven't tested it for performance against
any other solution, yet. It also allows the database to be local, e.g. 
in a file and even allows for updates of an object's interface to some 
degree.

-- 
Nils Hoffmann                                    phone:    +49-521-106-4335
Universitaet Bielefeld                            room:             U10-138
Techn. Fakultaet, AG Genominformatik 
Nils.Hoffmann at CeBiTec.Uni-Bielefeld.DE
33594 Bielefeld, Germany     http://www.cebitec.uni-bielefeld.de/~hoffmann/