RE: [ZODB-Dev] Question about BTree transaction data
Excellent! This is exactly what I needed. For reference, I attach your code and I hope it will get referenced by search engines :). Attached History.py is an enhancement of OFS.History that enables read access to old revisions of an object, even if that object has persistent subobjects. Author: Dieter Maurer Thanks a lot. Pascal -Message d'origine- De : Dieter Maurer [mailto:[EMAIL PROTECTED] Envoyé : jeudi 13 avril 2006 21:56 À : Pascal Peregrina Cc : zodb-dev@zope.org Objet : RE: [ZODB-Dev] Question about BTree transaction data Pascal Peregrina wrote at 2006-4-13 11:26 +0100: So, if I use HistoryJar to load a BTree from a given old state, are you sure HistoryJar will correctly load all the BTree subobjects (sub BTrees and Buckets)? I got the impression, reading HistoryJar code, that it might load current state of subobjects, not old states... :( The HistoryJar I spoke of is an improvement over the one you find in OFS.History. My HistoryJar binds persistent subobjects to itself. This way, not only the main object is loaded with the state at a given time but all its subobjects (and subsubobjects, etc.) as well. It works not only for atomic objects (those without persistent subobjects) but with arbitrary object hierarchies. All you need for this to work is to ensure that persistent subobjects are not associated with the original (the current time) connection but remain associated with the HistoryJar. I posted my HistoryJar implementation. Please, search the archives... It will require modifications to work for ZODB 3.4 or higher, as connection handling drastically changed between ZODB 3.2 and ZODB 3.4 -- but it will not be difficult to extends for these ZODB versions (once you know, that the essential thing is to preserve the connection for persistent subobjects)... -- Dieter ** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. www.mimesweeper.com ** History.py Description: History.py ___ 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] Question about BTree transaction data
Dieter Maurer wrote: Pascal Peregrina wrote at 2006-4-12 08:35 +0100: I use FileStorage (via ZEO). I have switched a big dictionary from PersistentMapping to BTree. In the past, it was easy to compute added/deleted keys from states (cause PersistentMapping state contains the whole dictionary, so it was only a matter of getting the keys and comparing them with previous state keys). What do you mean by state? What you get with obj.__getstate__()? I'd hazard a guess that Pascal is trying to write conflict resolution code. BTrees already have conflict resolution code. I'm not sure it can be improved upon. cheers, Chris -- Simplistix - Content Management, Zope Python Consulting - http://www.simplistix.co.uk ___ 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] Question about BTree transaction data
Replied to quickly... So, if I use HistoryJar to load a BTree from a given old state, are you sure HistoryJar will correctly load all the BTree subobjects (sub BTrees and Buckets)? I got the impression, reading HistoryJar code, that it might load current state of subobjects, not old states... :( Pascal -Message d'origine- De : [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] De la part de Pascal Peregrina Envoyé : jeudi 13 avril 2006 11:27 À : Dieter Maurer Cc : zodb-dev@zope.org Objet : RE: [ZODB-Dev] Question about BTree transaction data HistoryJar is what I was looking for !! Thanks ! Pascal -Message d'origine- De : Dieter Maurer [mailto:[EMAIL PROTECTED] Envoyé : mercredi 12 avril 2006 19:41 À : Pascal Peregrina Cc : zodb-dev@zope.org Objet : RE: [ZODB-Dev] Question about BTree transaction data Pascal Peregrina wrote at 2006-4-12 08:35 +0100: I use FileStorage (via ZEO). I have switched a big dictionary from PersistentMapping to BTree. In the past, it was easy to compute added/deleted keys from states (cause PersistentMapping state contains the whole dictionary, so it was only a matter of getting the keys and comparing them with previous state keys). What do you mean by state? What you get with obj.__getstate__()? In this case, you can indeed not compute added/deleted keys alone from the current and a previous state of the tree alone. You must also take into account the state of children... ... So could you give me a little more details about what you mean? (or of course point me to some example/resources on the net) Search the mailing list archive (for zope@zope.org or zope-dev@zope.org) for a post from me about HistoryJar. This is a speciallized ZODB connection that loads the state of objects as it was at a given time. In this, I do not mean state technically as the result of __getstate__ but as the complete object state. You can use such a historical object in the same way as you use a current object (apart from not being able to modify it). Especially, you can ask a historical BTrees.XXBTree instance for all its keys and compare this to all the keys of the current object. -- Dieter ** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. www.mimesweeper.com ** ___ 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 ___ 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] Question about BTree transaction data
I use FileStorage (via ZEO). I have switched a big dictionary from PersistentMapping to BTree. In the past, it was easy to compute added/deleted keys from states (cause PersistentMapping state contains the whole dictionary, so it was only a matter of getting the keys and comparing them with previous state keys). I can't see how to do so with BTree states, which look much more complicated... So could you give me a little more details about what you mean? (or of course point me to some example/resources on the net) Thanks. Pascal -Message d'origine- De : Dieter Maurer [mailto:[EMAIL PROTECTED] Envoyé : mardi 11 avril 2006 21:57 À : Pascal Peregrina Cc : zodb-dev@zope.org Objet : Re: [ZODB-Dev] Question about BTree transaction data Pascal Peregrina wrote at 2006-4-10 09:04 +0100: I would like to know if from BTree state data, it is possible to compute which keys were added/deleted. Of course not from a single state: it just tells you about the current keys, not about their history. If you are using a storage with history (e.g. FileStorage), then the history can allow you to retrieve earlier states. Comparing the current and some earlier state allows you to determine additions/deletions (to some extend). -- Dieter ** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. www.mimesweeper.com ** ___ 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
