Re: [ZODB-Dev] Re: Historical Persistent References -- Feedback Wanted!
Dieter Maurer wrote: Matt Hahnfeld wrote at 2006-3-13 14:33 -0500: ... I found your code a while back and actually looked it over quit a bit before I started coding the solution I attached. Would you be able to explain how it works? It works through a special HistoryJar (for some unknown reason, the ZODB uses jar as a term for a ZODB connection). This goes back to early BoboPOS versions and is based on the notion of a pickle jar. Jim -- Jim Fulton mailto:[EMAIL PROTECTED] Python Powered! CTO (540) 361-1714http://www.python.org Zope Corporation http://www.zope.com http://www.zope.org ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org http://mail.zope.org/mailman/listinfo/zodb-dev
Re: [ZODB-Dev] Re: Historical Persistent References -- Feedback Wanted!
Matt Hahnfeld wrote at 2006-3-13 14:33 -0500: ... I found your code a while back and actually looked it over quit a bit before I started coding the solution I attached. Would you be able to explain how it works? It works through a special HistoryJar (for some unknown reason, the ZODB uses jar as a term for a ZODB connection). When you create a HistoryJar, you pass in a serial (a timestamp). Objects retrieved via this connection have (all) the state as it was current at the time identified by the serial. The implementation uses the ZODB history for an object which is the sequence of the object's states corresponding to the various object modifications. The state with the smallest serial not smaller than the HistoryJars serial is retrieved by the HistoryJar (if any). Most of the implementation is just doing the above operations in an efficient way. ... BTW, if your posted solution is still viable, I'd be more than happy to help port it to 2.8, or help out in whatever other capacity I can. I had to override a few (I think a single) Connection methods; with Zope 2.8 (and upward) almost surely some more/other methods need overriding (as connections and transaction handling have changed quite some bit). -- Dieter ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org http://mail.zope.org/mailman/listinfo/zodb-dev
[ZODB-Dev] Re: Historical Persistent References -- Feedback Wanted!
On Mon, 13 Mar 2006 19:54:43 +0100, Dieter Maurer wrote: To make a long story short, the current implementation of historicalRevision in Zope's OFS/History.py calls oldstate() in ZODB/Connection.py. The serializer then calls getState() in ZODB/serialize.py (class ObjectReader), which sets up an unpickler to handle persistent references by overriding _persistent_load(). Unfortunately, when the _persistent_load subroutine comes across a persistent reference, it either loads the CURRENT referenced object from the ZODB (using the oid and ZODB/Connection.py's get()), or loads the CURRENT referenced object from cache. It does not take 'tid' into account when it loads persistent references. A long time ago, I posted code (I think to zope-dev@zope.org) that does it for you in the right way. It defines a HistoricalConnection which retrieves objects with a state as of a given time. You might search for historicalRevision and HistoryJar to locate the post. Zope 2.8/ZODB 3.4 broke my implementation but it would probably not too difficult to get fixed. Dieter -- I found your code a while back and actually looked it over quit a bit before I started coding the solution I attached. Would you be able to explain how it works? A lot of your code made sense, but I was a bit overwhelmed by some of it. Here's the link: http://article.gmane.org/gmane.comp.web.zope.zodb/6327 BTW, if your posted solution is still viable, I'd be more than happy to help port it to 2.8, or help out in whatever other capacity I can. ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org http://mail.zope.org/mailman/listinfo/zodb-dev
