-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Jim Fulton wrote: > Garrett Smith wrote: > >> The use of INameChooser is useful for picking names that don't conflict >> across serial transactions. But this approach is problematic when two or >> more transactions are tying to add objects to a container at the same >> time. Because 'choose name' relies on its isolated version of a >> container, multiple threads are destined to choose the same name >> (assuming non-random algorithm), resulting in a write conflict. >> >> In some cases a write conflict is a normal and healthy thing to get, >> particularly if you let users edit the same object at the same time >> without care. But adding new objects to a container when the names are >> chosen by the system should not cause this problem. E.g. if the objects >> use unique keys, the BTree conflict resolution should gracefully handle >> the concurrent adds. >> >> The only solution that occurs to me is to use an alternate persistence >> mechanism (e.g. a file or database) for 'next name' sequences and >> control access to it via a thread lock. >> >> Is there a way to do this in the ZODB without the use of some external >> file-locking/update mechanism? >> >> Does this problem even make sense to people, or have I lapsed into >> garbled nonsense (again) :-) > > > It's only a problem for large shared containers that people are > very likely to add to at the same time, so it's a somewhat > specialized problem. > > If people don't actually care about ids, you could generate them > randomly. > > Another common scheme is to use high-precision times in th names.
The current thread ID would also give you another source of variation. Tres. - -- =================================================================== Tres Seaver +1 202-558-7113 [EMAIL PROTECTED] Palladion Software "Excellence by Design" http://palladion.com -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.5 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD4DBQFCtAt9+gerLs4ltQ4RAmPWAKCfl1GINJbVTj1fyeNg1nZoxlJkhQCXZmUp iCseoqxbFwU73ZGcBW4Q2w== =1Whk -----END PGP SIGNATURE----- _______________________________________________ Zope3-dev mailing list Zope3-dev@zope.org Unsub: http://mail.zope.org/mailman/options/zope3-dev/archive%40mail-archive.com
