Nice post! You mentioned that you implemented this wrapper for backups. Apart from creating a virtual file system for sandboxing perhaps, isn't this generally slower? Maybe I am not getting the exact purpose of this task.

Slower than what? This is for creating encrypted versions of your files before you back them up, so your backup program will only see encrypted files.

This app proves also very helpful if you use Nginx: https://github.com/andreiko/django_graceful

> Django Graceful is a set of commands for deployment

> of django projects as fastcgi backends.

Or just use uwsgi[1] and supervisord[2] if possible.

[1] http://uwsgi-docs.readthedocs.org/en/latest/

[2] http://supervisord.org/

Is this version compatible with 1.4.2 or will it require a full data dump/restore?

If you have a 1.4.2 cluster you can do a rolling upgrade to 2.0 without doing a "dump/restore". Please remember, this is a tech-preview, don't upgrade your production cluster to 2.0 until it's been released for production use. Feel free to test drive this preview, and if you do so please send us feeback! #disclaimer I work for Basho

OK, thanks for answering!

Nice analysis. Hope you don't mind me adding that by omitting terms of the Taylor series you do have some loss of precision, however small. Also, solving linear equation systems may even introduce instability as the following must be preserved: http://en.wikipedia.org/wiki/Diagonally_dominant_matrix

The point is that when you're considering the Taylor series for a dual number argument, you don't lose any precision, because higher powers of the "imaginary" part of the dual number vanish. The example he gives is

    f(a + be) = f(a) + f'(a)be + 0.5 * f''(a) b^2 e^2 + O(e^3)
              = f(a) + f'(a)be

because e^n=0 for all n>1. This isn't an approximation - it's an exact relationship for dual numbers!

You will lose some precision by using floating point numbers instead of an arbitrary-precision real number type, but this is a limitation of the machine you're working on. The method is exact.

No, the coefficients of the Taylor series are the exact derivatives, assuming the actual arithmetic were exact (it's not, because IEEE 754). There's no loss of precision there.

I suppose someone could incorporate a procedure which strips down unnecessary strings from code files ("minifies"), especially comment blocks, during the deployment process, thus maintaining a nice development codebase while not having questions over performance.

Yes, definitely breaking into smaller paragraphs will make it far more readable.

Thanks gpsarakis. Appreciate the feedback.

You could also consider Google AppEngine https://developers.google.com/appengine/docs/python/

Are you using MySQL in your example?

  > id is an incremental value, I choose 11 as a length 
  for this primary key but this value is defined 
  by the number of pages you’ll need to index

This is a bit confusing. You'd generally be better off with INT UNSIGNED as it doubles the range for auto-increment columns.

Also the visited field would be better to be represented by a timestamp, choosing the right datatype does matter in large tables.

Nice to know about the Dropbox integration. Really good work, keep it up!

Just to clarify: I am not the creator of this app, just came across it while searching how to create simple diagrams and thought it might be helpful sharing it.