Re: Re: ZopeUndo.Prefix is still used

On Sun, Aug 14, 2016 at 2:41 PM, Hanno Schlichting <[email protected]>
wrote:

> On Sun, Aug 14, 2016, at 18:37, Jim Fulton wrote:
>
> On Sun, Aug 14, 2016 at 9:04 AM, Hanno Schlichting <[email protected]>
> wrote:
>
> Undo management in Zope2 is now available in its ZMI control panel on
> each configured database object, instead of contextually on ZMI folders.
>
>
> I'm not sure I understand this.  FWIW, if we need the ability to filter
> undoLog/undoInfo at some point, I'd be happy to discuss some sort of
> specification language based on data structures that don't require
> instances.
>
>
> Sure, that makes sense for ZODB in general.
>
> From my experience with Zope2/CMF based projects, they all just tend to
> use the ZCatalog and most of them tend to index some kind of modification
> time. As a result almost all transactions actually end up changing not just
> a content object somewhere, but also the exact same BTree bucket inside the
> ZCatalog and this bucket sees constant bucket splits.
>

Ah, right.


>
> As a result it almost never works to selectively undo some transactions,
> but in this context it only works to undo all transactions from most
> current back to a prior state, including all transactions in between.
>
> That's what the ZMI on Zope2 master still allows, by simply showing all
> transactions and allowing you to undo them in order for each configured
> storage.
>
> Hope that is a bit clearer,
>

Yup. Thanks.

Jim


-- 
Jim Fulton
http://jimfulton.info

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