[ZODB-Dev] Fixing POSKeyErrors :-)

[Paul Winkler]

On Wed, Feb 13, 2008 at 07:34:20PM -0500, Jim Fulton wrote:
>
> On Feb 13, 2008, at 6:14 PM, Binger David wrote:
>
>>
>> On Feb 13, 2008, at 3:58 PM, Jim Fulton wrote:
>>
>>> Note that, IMO, some of the best use cases for multi databases are 
>>> separating catalog and session data from regular content.
>>
>> Could you say more about what the benefit of this separation is,
>
> Catalogs and session data change much faster than content.  It makes sense 
> to pack these more frequently.  On large system, it provides the ability to 
> spread load over multiple servers, if necessary.

Also, as I understand it, you can get more benefits from the "regular
content" ZODB cache if you're not constantly moving tons of catalog
data through it, so there's a performance win.

We've been discussing doing this for openplans.org... one question
that came up that none of us knew the answer to: If I undo some
changes to content, what happens to the index values for that content?
Does undo fire an ObjectModifiedEvent? If not I'd guess that the
catalog will still contain pre-undo data.

-- 

Paul Winkler
http://www.slinkp.com