[infinispan-dev] rethinking ISPN transactions

[Galder Zamarreño]

On Nov 8, 2013, at 4:28 PM, Mircea Markus <mmarkus at redhat.com> wrote:

> 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

So, they're always sync, right?

> 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

+1. So, if you remove RC, and we only have RR, you can get rid of the isolation level configuration property altogether? We don't implement SERIALIZABLE, nor READ_UNCOMMITTED.

> 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)

+1

FYI, this means that the default OL behaivour changes. To be more precise, here's [1] a Gist with the difference in expectations for default configuration.

[1] https://gist.github.com/galderz/9ba22e47116906a750d7

> - 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

> 
> 
> [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)
> 
> 
> 
> 
> 
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--
Galder Zamarreño
galder at redhat.com
twitter.com/galderz

Project Lead, Escalante
http://escalante.io

Engineer, Infinispan
http://infinispan.org