[Zope-dev] Re: DBTab and CMF

[Shane Hathaway]

Fabio Paracchini wrote:
> Hi Shane,
> 	I was able to successfully install and use DBTab & BDBStorage, and
> to
> migrate a legacy archive of about 20Gb of Office documents.
> 
> Now I run in this situation: I'd like to partition those archives, so that
> everything is not in a single giant DB, but is split among several smaller
> DBs.
> 
> DBTab works perfectly if you have a 'standard' Zope environment, i.e. if you
> have Mountpoints/Folders.
> 
> I was not able to mount a different storage beneath a CMF Folder, it seems
> that inside DBTab's code a mount point is derived from Folder, and that is
> not shown in a CMF/Plone site.
> 
> Do you have any clues about using DBTab's mount points in a CMF/Plone site ?

Tres and I stumbled upon the right way to do this yesterday: you make a 
copy of your database first, then in the primary database you delete the 
items you want to load from the secondary database and replace them with 
mount points.

A concrete example: Let's say for a moment that you have one big Data.fs 
and you want to move the folder at /Site/Documents to its own database. 
  First make a copy of Data.fs called "Documents.fs".  Set up dbtab.conf 
to open both databases and mount /Site/Documents from Documents.fs.

When you restart Zope, initially nothing will have changed--the 
documents are still in the main database.  Visit the folder at /Site and 
delete the Documents object.  (If you have sufficient backups, this 
shouldn't make your heart race. ;-) )  Now add the DBTab mount point. 
/Site/Documents will come back, this time loading from Documents.fs. 
Rather than a Folder, the object at /Site/Documents will be whatever 
kind of object it used to be, whether it was a CMF PortalFolder or a 
Zazzywag Kanuliputz.  Everything will work like it did before--you don't 
even need to restart a second time.

You'll want to use DBTab 1.1, BTW--I think it solves all the former 
strange bugs, and it's significantly faster.

You'll have to adapt for BDBStorage.

> BTW is there a better way to ask you those questions, instead of mailing you
> directly, and also make you and the Zope community happier ?

I CC'ed zope-dev@zope.org.

Shane