[infinispan-dev] rethinking ISPN transactions

[Mircea Markus]

Hey guys,

Several things were discussed lately([1],[2],[3],[4]) around our transaction support. Here's some some thoughts I have around re-modeling transactions for 7.0:

1. Async options for commit/rollback
- they don't really make sense as a user you don't get any guarantee on the status of the transaction
- they complicate the code significantly
- I think they should be removed

2. READ_COMMITTED
- it has the same performance as REPEATABLE_READ, but offers less guarantees. 
- unlike REPEATABLE_READ, it also behaves inconsistently when the data is owned by transaction originator
- I think it should be removed

3. Optimistic tx without Write Skew Check (WSC)
- well, without WSC the transactions are not optimistic by definition 
- they are something else: an batch update of multiple key/values. If the batch is successful you know the update was atomic. If it failed you don't get any guarantee
- suggestion: optimistic tx should *always* have WSC enabled (no option to configure it)
- build our batching functionality on top of what currently is optimistic tx without WSC and document it as such

4. Remove 1PC option
- I'm not totally sure about it, but does it really make sense to have 1PC as an option? they don't offer any consistency guarantees so async API + non tx do about the same thing
 

[1] http://markmail.org/thread/a7fjko4dyejxqgdy
[2] https://github.com/infinispan/infinispan/pull/2177
[3] http://infinispan.markmail.org/thread/nl2bs7rjvayjcybv
[4] http://infinispan.markmail.org/thread/vbg6g4otu7djazbc


Cheers,
-- 
Mircea Markus
Infinispan lead (www.infinispan.org)