[ZODB-Dev] multiple subtransactions

[Christian Robottom Reis]

We currently are unable to have multiple subtransaction "checkpoints" in
the ZODB. This means that, while you *can* issue multiple commit(1)s and
have your state incrementally persisted [temporarily to storage],
issuing multiple abort(1)s won't take you back to the original state
(the state that existed before the modifications in this transaction) --
they at most take you back to the last time you called commit(1).

Would it be hard to alter the ZODB to support this feature? I understand
there may be code that relies on the current behaviour, but we could use
a slightly different API; perhaps something like commit_sub(), which
returned an ID for the subtransaction, and which could be passed to
abort_sub() (and if none was supplied, revert to the state of the last
non-aborted commit(1) issued)?

Are there other suggested alternatives that already work? 

Take care,
--
Christian Robottom Reis | http://async.com.br/~kiko/ | [+55 16] 261 2331