[infinispan-dev] rethinking ISPN transactions

[Mircea Markus]

On Nov 12, 2013, at 12:56 PM, Galder Zamarreño <galder at redhat.com> wrote:

> 
> 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?

Yes

> 
>> 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.

yes, the isolation level would 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)
> 
> +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

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