Florent Guillaume wrote at 2006-6-30 02:46 +0200: > ... >> that's interesting. I did a test once to see what effect it would have >> to add objects with a completely random id to a BTree folder (OOBTree in >> that case) instead of using the object's type nam and add a number at >> the end - and the result was the opposite in term of read performance. >> Looking up keys was much faster if the ids followed a pattern like: >> >> - something-1 >> - something-2 >> ... > >Sure, in single-threaded mode this will decrease performance because the >keys are spread randomly among all the buckets so many more buckets get >written. > >But in multi-threaded mode, this very spreading leads to better conflict >resolution behavior.
But still can reduced performance... That's why the catalog uses the initial id randomly but then assigns id's (within a single thread) sequentially. -- Dieter _______________________________________________ Zope maillist - Zope@zope.org http://mail.zope.org/mailman/listinfo/zope ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope-dev )