Write transactions when request time out

[Krishna Chaitanya Thanuku]

Hi all, my name is Chaitanya. I am newbie to google app engine. I have been reading about app engine from yesterday. I read about the quota and limits too.

I have a doubt regarding this. For instance, suppose that I am creating 10,000 objects and saving all those to the datastore in a single transaction(DataStoreService). I guess dataStorService.put(entity) is like a Hibernate transaction. Now that, after putting 5000 objects to the datastore the 30 seconds limit for a request execution has been timed out.

Now what about the rest of the 5000 objects? I head here that

With the App Engine datastore, every attempt to create, update or delete an entity happens in a transaction. A transaction ensures that every change made to the entity is saved to the datastore, or, in the case of failure, none of the changes are made. This ensures consistency of data within an entity.

Is it true? If the transaction fails, the rest of 5000 objects are also discarded from the datastore?

Can anyone help me understand this better?

Thank you all in advance, good day.