[infinispan-dev] replacing the (FineGrained)AtomicMap with grouping

[Emmanuel Bernard]

On 21 sept. 2013, at 18:32, William Burns <mudokonman at gmail.com> wrote:

>> [Technically it would be awesome to be able to be able to rely on RR
>> but it doesn't work as in databases - it doesn't snapshot the version
>> of entries not touched yet - so we have to compensate at a higher
>> layer..]
> 
> The repeatable read implementation is the same as Oracle using multi
> versioned entries.  It sounds like what you are talking about is
> Serializable which doesn't scale

You mean Oracle DB?
Then no I don't think you are correct unless something has changed in this area in Infinispan. Oracle achieves ANSI RR with snapshot isolation - which offers a contract between RR and SERIALIZABLE.
But that's not their default isolation level. 

Regardless of that my understanding of Infinispan's implementation is that in the group approach - and I believe FGAM-, I could update different "columns" of the same "row" - in OGM terms - in parallel provided that the columns are different. This is not the case of RDBMS RR as I understand it. To work around that your application must have a version column that you update for each change. 

I am a bit rusty on these subjects so feel free to correct me.