[Zope3-dev] Re: [Checkins] SVN: zc.dict/trunk/ Initial version of zc.dict -- a persistent BTree based "dict".

[Bernd Dorn]

On 03.07.2007, at 20:39, Albertas Agejevas wrote:

> Log message for revision 77375:
>   Initial version of zc.dict -- a persistent BTree based "dict".
>
>
hi

this package matches a use-case we have often, very nice!

just some thoughts

use a BTree.Length object to hold the length, otherwise you will get  
loads of write conflicts, see also what i have done in  
zope.app.container this week

there is also a small bug in __setitem__ ... if the key exists, the  
len is increased without a key being added (note, in my  
zope.app.container this is not the case because you get a duplication  
error if this happens)

you should use __setitem__ internaly for update etc, because  
computing the length of a btree takes very long time, it has to fetch  
all buckets from zodb. if u use zeo it gets even slower

regards, bernd