Image as database (was: Re: Minnow WIKI Migration)

Lex Spoon lex at cc.gatech.edu
Wed Oct 25 19:49:31 UTC 2006


Bert Freudenberg <bert at freudenbergs.de> writes:
> I thought we were having a serious discussion, and not just pointing
> fingers at RAM prices. Or pointing to non-existent VM technology, as
> you did in another thread.
> 
> I stand by my assessment that holding *everything* including all
> versions of all pages and also all uploaded files in RAM is just
> plain stupid.

I am not sure about just plain stupid, but it's at least a very risky
thing to do.  Dealing with such a large image is almost certainly
harder than rewriting it not to need so much memory.

The challenge to the hardware is just the beginning.

Squeak's VM is not at all made for such big images.  I saw "funny" GC
behavior with my 75 MB images for Chuck.  I'd want to run some
experiments before entrusting it to a 2 GB image.  Probably you'd have
to code your software carefully w.r.t. memory management.

The other problem leaping out to me is managing the data over time,
especially when corruption inevitably occurs.  Are you ready to open a
Squeak just to debug the data?  Are you aware that Squeak can lose
images in some cases?  [1] With the real data in simple files or in a
database, these issues are much less risky.


Overall, I am not opposed to jumping ship from ComSwiki.  Indeed, it
would be excellent to use wiki software that is maintained by someone
highly motivated.  Even given that, however, should we not wait until
we have something that is *already* better than ComSwiki?

-Lex


[1] http://lists.squeakfoundation.org/pipermail/squeak-dev/2001-January/009731.html





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