[petsc-dev] Writing rich state

[Jed Brown]

On Wed, 24 Feb 2010 09:25:39 -0600, Dmitry Karpeev <karpeev at mcs.anl.gov> wrote:
> Here's the main problem that I see: are file attributes stored in the database
> fixed?  That could be somewhat inflexible (what if some attributes don't apply
> to a given file?  what if I want to add another attribute?).  The alternative
> is to manage this with (key,value) string pairs (e.g., ("precision",
> "double") etc).

Some attributes would be mandatory, but they certainly need to be
extensible.

> Is there a way to encode that in a relational database and maintain
> good performance?

I think that to first order, performance is a non-issue because it's so
small compared to the real files.  I would expect that even with a
million time steps, it would be pretty hard to make the DB a bottleneck.
In any case, I think it will be more challenging to make the DB smart
enough than to make it fast enough.  Maybe someone who knows something
about databases (Matt?) can comment.

Jed