Re: [ZODB-Dev] Any risk about foreign zodb references
Le 18/07/2011 18:16, David Glick a écrit : On 7/18/11 9:08 AM, Alexandre Garel wrote: Hello, We are building up an application where we use multiple zodb instances. Indexation is done using solr. zodb are served through zc.zodbwsgi. ZODB connections are set only on-demand, upon traversal. Each zodb has its intid local utility. Each object also has a uuid. I have a zodb with global parameters objects on /params and distinct zodb as /foo /bar /baz and so on. Objects in a zodb may reference objects of the same zodb or of /params. I have two possible strategies : - either store uuid of referenced objects and retrieve objects from solr (which will give me a zodb name + intid of object) - either directly reference the objects of /params Of course second option seems better and more natural. I read http://svn.zope.org/ZODB/trunk/src/ZODB/tests/multidb.txt?rev=99605view=markup and using pdb on databases = request.environ['zodb.connection'] I can see the zodb.databases map which is ok. I also know that _p_oid is unique and _p_jar handled for each object so I feel confident on this side. So before I dive into this, is this kind of cross-database reference used on production applications. Is there any-risk or any trick to be aware ? Using cross-database references can be treacherous, because the garbage collection that occurs when packing a ZODB the typical way is not aware of the cross-db references. So if there's an object in one db that is only referenced from a different db, it will get garbage-collected during packing. You can probably use http://pypi.python.org/pypi/zc.zodbdgc instead of standard packing to avoid that problem. Thanks for the advice. I normally won't fall in this case as my params objects are contained in parents and must exists even when all other zodb would not. Thanks for your feedback. -- Alex Garel ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev
Re: [ZODB-Dev] RelStorage zodbconvert, ConflictError on Zope2 startup
On 07/18/2011 02:16 PM, Sean Upton wrote: On Fri, Jul 15, 2011 at 5:35 PM, Shane Hathawaysh...@hathawaymix.org wro= te: I am thinking of changing the memcache code to use a random per-database = key prefix. =A0If I had done that already, you would not have run into this problem, since clearing the database would cause RelStorage to use a new = key prefix. =A0Your old memcache data would have been ignored. +1, and it sounds like by consequence of design, this would be necessarily backward compatible with existing installations of 1.5.0? Yes, it should be fully compatible with existing installations. Shane ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev
