[ZODB-Dev] ZODB4 project plan

[Guido van Rossum]

> Speaking of YAGNI's and ZODB4, does anybody have any actual use cases for 
> nested transactions?  I notice that's listed on the project plan, but I 
> thought that discussion on the Persistence-SIG suggested them to be overkill.
> 
> The main use case for "subtransactions" in ZODB presently, is to free up 
> cache space by flushing dirty objects.  But that use case has nothing to do 
> with transaction semantics; when you add a subtransaction for that, you do 
> it essentially as a "special case" fix for high-write-volume 
> operations.  So as Shane pointed out, providing data managers with a 
> "flush()" method would not only address the specific issue in context, it 
> would be easier to explain code that uses it.
> 
> Interestingly, from the comments so far about versions, it sounds as though 
> improved "long transaction" support would be much more valuable than nested 
> transaction support for many kinds of applications.

Now's a poor time to ask -- Jeremy's on vacation until next week.

--Guido van Rossum (home page: http://www.python.org/~guido/)