[CalendarServer-dev] Hoping for a sanity check: Chapter 2

Mark Cockfield mark.cockfield at gmail.com
Tue Oct 28 18:03:03 PDT 2008

Hi Wilfredo,

Thanks for the reply.

Yep, reporting makes me shudder. I may look at the possibility of loading
the file system store into the application database when I need to create
reports. If the calendar object properties are separate columns, the
possibilities become interesting.

I hadn't really considered atomicity from just a calendar store perspective,
very valid point. And since your repository is comprised of discrete
entities, cleanup become challenging. I was hoping, and I'm not completely
convinced that it is hopeless, that I could make application and Calendar
Server updates atomic. It seems to me that since I am planning on adding my
PyAMF Twisted gateway as a caldav pluggin and will be using SQLALchemy and
PostgreSQL, that there should be a way to handle the SQLA database sessions
and nested transactions to theoretically pull it off.

So for meetings are you thinking of an audit trail? Would each attendee have
a copy of the master? By edits to you mean counter proposals or personal
descriptions and comments?

Ticket #269 was actually the first to catch my eye, left me with foreboding
regarding RDBMS, then I hit #198 and #132...okay all is not lost. Another
thought that has been kicking at the back of my head is MVC. A more loosely
coupled architecture would have benefited me on the the view side as it
would facilitate integrating emerging technologies in the client domain.
Strip out the HTTP protocol and you are left with a command syntax: method
is your command, header and body become arguments. So I guess a questions
becomes: does the CalDAV standard require a tight binding to a specific
protocol? Although, it seems to me the Twisted architecture does. On the
model side, SQLAlchemy allows me switch between a SQLite memory database and
several flavors of RDBMS by changing one line of config. Then a question
here becomes: is it worth maintaining a file system option in the



On 10/28/08 2:37 PM, "Wilfredo Sánchez Vega" <wsanchez at wsanchez.net> wrote:

> On Oct 16, 2008, at 8:50 PM, Mark Cockfield wrote:
>> Finally, I would be interested in hearing what Wilfredo's and David's
>> motivation was in creating their respective tickets regarding data
>> persistence.
>  I added couple of comments to http://trac.calendarserver.org/ticket/198
> .
>  Atomicity is my greatest concern at the moment.
>  http://trac.calendarserver.org/ticket/269 is important regardless
> of whether we use a DB or not.  We have some administrative functions
> that we'd like to be able to implement without running a server or
> instantiating HTTP resources and doing HTTP things to them.  The data
> model and protocol are inter-twined right now, and that's just poor
> abstraction.
> -wsv

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