If all keys are known in advance, how is it different from starting a pessimistic transaction and invoking getAll() on those keys? Introducing a new concept with such restrictions does not makes sense to me.
2016-02-04 1:27 GMT+03:00 Dmitriy Setrakyan <dsetrak...@apache.org>: > Igniters, > > I keep hearing questions from users about the snapshot isolation. Currently > ignite provides Optimistic and Pessimistic > < > https://apacheignite.readme.io/docs/transactions#optimistic-and-pessimistic > > > transactions [1]. This modes ensure that transactional values are > consistent with each other on 1st access of each value. > > However, some use cases require that transactional values are consistent > with each other not at 1st access, but at transaction start time. After > giving it some thought, I think we can support it with minimal effort, if > we add a few restrictions. For example, we can easily support it if users > specify all the keys at the beginning of the transaction, for example > > 1. User tells Ignite which keys he/she plans to transact on > 2. Ignite preemptively acquires locks on all these keys > 3. After locks are acquired, user has assurance that values will not > change outside of this transaction and are consistent with teacher. > 4. Locks are released upon commit > > The above algorithm will also perform better, as the initial looks will be > acquired in bulk, and not individually. > > Thoughts? > > [1] > https://apacheignite.readme.io/docs/transactions#optimistic-and-pessimistic >
