I have the transactions working, but it is not fully compatible with
web2py DAL, but it could be soon ( needs type coercion, db.table.ALL,
etc)  Also in web2py, you cannot set the entity group when inserting,
so transactions will only involve 1 record.  (eg atomically read/
modify/write a counter in a transaction)

If you needed transactions immediately, you could do this:

from google.appengine.ext import gdb

def txn():
  post = db.posts[post_id]
  post.update_record(title='foo')
  return post

post = gdb.run_in_transaction(txn)

On a side note, I have batch operations working too. But I recently
read that batch operations are just O(n), which unfortunately means no
joins or efficient batch operations will be possible for now, but I
have not benchmarked it on the real google datastore to know for sure.

Robin


On Feb 19, 3:31 pm, sebastian <[email protected]> wrote:
> Hi All,
>
> is there any schedule for the GAE transactions/entity groups ?
>
> if not, how would it be the best way (web2py upgrades compatible !) to
> use entity groups and transaction with web2py ?
>
> thanks
>
> On Jan 19, 2:59 pm, Robin B <[email protected]> wrote:
>
> > > Groups under the DAL to be a single record. Since Big Table
> > > transactions are limited to one Entity Group pertransaction, this
> > > means that we are limited to one record pertransaction. Right?
>
> > You have it right.
>
> > > In the example above, 'count' is just an example of some arbitrary
> > > column in the record, right? Can I have multiple assignments? Can I
> > > mix lambda and non-lambda assignments? E.g.:
>
> > >     row.update_record(count=lambda r: r.count+1, vote_score=lambda r:
> > > calculate_vote_score(), preference='blue')
>
> > Yes, you would be able to mix lamdas/functions and values.
>
> > On the subject of passing lamdas as attributes, the field.default=
> > should also recognize any lambda/callable and call it on demand:
>
> > def uuid():
> >   import uuid
> >   return uuid.uuid4()
>
> > db.table.created_at.default=t2.now
> > db.table.uuid.default=uuid
>
> > Robin
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