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pcplantdb - Re: [pcplantdb] technical details, plan, re: synthesis

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  • From: "John Schinnerer" <john@eco-living.net>
  • To: pcplantdb@lists.ibiblio.org
  • Subject: Re: [pcplantdb] technical details, plan, re: synthesis
  • Date: Mon, 2 Aug 2004 21:39:47 -1000 (HST)

Aloha,

Yikes, I'm suddenly drowning in mail. May take a few days to catch up.

> o Zcatalog is for Zope objects. This still may be what we want, but
> I really haven't spent much time looking at Zope itself.

A zope product is afaik pretty much whatever you want to do/are able to do
in python, with some obligatory hooks into the rest of zope. So as far as
I know about it, if you can create the object in python it can be a zope
object and be cataloged in zcatalog.
I've only done a few relatively simple objects so far myself - and, I'm
not aware of any reason why much more complex ones wouldn't work the same
in general.

The only restrictions I know of for sure are in python script objects
created directly in zope, and those are very wise restrictions for
security purposes (basically to keep people from exploiting python via
zope to do naughty malicious nasty things like take over, lock up and
otherwise mess with the server...).

> There is a
> package for ZODB called IndexedCatalog
> <http://async.com.br/projects/IndexedCatalog/> which should provide
> the needed functionality independent of Zope. I don't know what we
> will end up using but I do think that we have the tools in the Zope
> package to do the job.

Afaik ZODB can itself be used independent of zope...maybe requiring that
package? Looks like you're already beyond me in researching this one.


> o Schema is more important to ZODB than I initially thought in the
> sense that when you have a working version and you add an attribute
> to an object only the newly created objects will have the complete
> set of attributes. In order to update the schema in
> preexisting/working objects you need to write custom scripts to
> traverse the objects in the database and add the attributes to them.

True, I have read a few things about this. There are some examples
somewhere of how to do this (zopelabs maybe?). The one I saw made it seem
pretty easy, but I don't recall how complex the underlying system was.

> So nobody really responded to my emails regarding the fact that 1) I
> need additional time to learn Zope and 2) I really only can commit to
> 30 hours a week. This definitely puts a skew on the Project Plan, and
> I'd like some feedback. According to the plan I am scheduled to
> complete around 200 hours of work by the end of August. Granted, my
> estimates are high estimates but I think it is unreasonably optimistic
> to assume that the current Project Plan will not be at least two weeks
> late by Sept 1. Not sure where to go with this.

I am fine with a flexible project plan timeline. As long as we all stay
up front with our situations/capabilities/resources as we go I think it
will work out OK.
Given that the majority of most of our time is being volunteered here, I
think it's only realistic to be flexible with the schedule.
Given that we may need to wait a while just to get some of our basic
resource in place, likewise.

Main thing is not to make non-changeable or unrealistic promises to grantors.

>
> Zope cons:
> o Big learning curve.
> o Unknown performance (speed).

It's not always fastest nor slowest I gather that some of the more recent
versions of 2.x have focused on speed and made some good improvements. I
know the zcatalog has been speeded up pretty dramatically since
2.4.something or so.
I found some case studies once that seemed to indicate it holds its own
with comparable platforms.
Possibly not with Chad's awesome custom stuff though. ;-)

John H may have some metrics from his system. The sites I do are pretty
low traffic, so not much to compare there.



John Schinnerer - MA, Whole Systems Design
------------------------------------------
- Eco-Living -
Whole Systems Design Services
People - Place - Learning - Integration
john@eco-living.net
http://eco-living.net






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