Re: Reg. persisting data in ZODB via forms
Tres Seaver <[email protected]>
| Newsgroups | gmane.comp.web.zope.devel,gmane.comp.web.zope.bluebream |
|---|---|
| Message-ID | <[email protected]> |
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 06/08/2011 01:40 PM, Marius Gedminas wrote: > On Wed, Jun 08, 2011 at 06:20:26PM +0530, Joe Steeve wrote: >> As I mentioned on a follow-up post, we figured the 'Persistent' part. :) >> >> On Wed, 2011-06-08 at 13:29 +0100, Laurence Rowe wrote: >>> My guess is that the ObjectModifiedEvent is dispatched to your >>> object's parent and causes something to change there, with the side >>> effect of storing your updated object. >> >> Even if the object's parent (a btree-container) had changed, will it >> attempt to force-store its entire child-tree? I am trying to imagine the >> effect of it on a huge tree. > > The smallest unit that is ever written to a ZODB is one persistent object > (with all its nonpersistent attributes/items, recursively). > > BTrees use multiple persistent buckets for their state and are very > efficient, storage-wise. But this only matters when you're > adding/removing items to a BTree. If you're modifying a persistent > object stored in a BTree, the BTree itself remains unmodified and does > not need to be re-written Likewise, if you modify a non-persistent attribute of a persistent object which also has some attributes which are themselves persistent, only that object is re-written. Tres. - -- =================================================================== Tres Seaver +1 540-429-0999 [email protected] Palladion Software "Excellence by Design" http://palladion.com -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk3vtXcACgkQ+gerLs4ltQ6fMQCfcdevBmf4yA3HBnZal/8map5h q2sAnj7acU3CjN2DACvCA2Ij213VvW/k =w9IP -----END PGP SIGNATURE----- _______________________________________________ Zope-Dev maillist - [email protected] https://mail.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - https://mail.zope.org/mailman/listinfo/zope-announce https://mail.zope.org/mailman/listinfo/zope )