[elephant-devel] Querying Advice

[Robert L. Read]

On Sun, 2006-11-12 at 23:17 -0500, Daniel Salama wrote:

> I believe (and hope) that we should have no problem mapping the GUI to
> the requests. Just out of curiosity (and I don't mean to divert from
> the topic of this thread): if you're using DCM for your konsenti (BTW,
> nice concept) site, how do you protect your in-memory data? Do you
> just write an image to disk every once in a while for back ups? How
> resilient is this to hardware failure and you loosing data since the
> last image (if that's your approach)?


DCM does write-through; any change in a data object is explicitly pushed
to the datastore via "register-obj".

If you can't fit your dataset into memory, then you will need to you the
"gdcm" file, which implements
a "generational" notion.  Every object has a generation, and you can
choose a directory strategy for 
each generation.  The obvious thing to do is to keep the "zero"
generation in memory, and everything 
in the datastore.  Thus access to the first generation is very very
fast, but when you reach into 
other geneations you pay the normal database retrieval cost.

The BDB files are probably larger because our serializer is not as
efficient as it could be.
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