On Aug 20, 2013, at 7:47 PM, Dale K. Henrichs <dale.henrichs@gemtalksystems.com> wrote:

Doru,

I would be willing to spend time into helping with a GemStone-based persistence solution ... I will be at ESUG in September so that would be a great time to discuss the issues ...

I know that you are not planning on being there, but perhaps I could meet with someone else who is familiar with the Moose requirements...there are several approaches that I think would make sense, but it really depends upon your requirements…

Thanks dale.
We could organize a skype meeting. I will be there. Usman/Guillaume are not coming but we can arrange a skype meeting.


In essence Moose has models that are graphs of objects like a code metamodel: a package contain classes, contains methods, Methods access IV, Methods access other methodds.
So as soon as we program something on top of FAMIX then we navigate pointers in this graph. We did an experiment (mooseOnTheWeb) with Amber as a client and Moose as a server. 
The point is that it is working when you do a query and then you get JSON objects (but just the shallow objects)  and if you need to work in the graphs you need to do multiple queries to get from shallowed information to the next one. 
Now in essence a solution with GS to me would mean to move Moose on GS on the long term and I'm not sure that this is the way to go. 
May be I'm wrong.

Stef


Dale

From: "Tudor Girba" <tudor@tudorgirba.com>
To: "Moose-related development" <moose-dev@iam.unibe.ch>
Sent: Tuesday, August 20, 2013 3:02:23 AM
Subject: [Moose-dev] Re: persisting moose models

Hi Fabrizio,

How large is the MSE file?

I understand your concern, but I do not think that a relational database would work well in this case. Probably much better would be a MongoDB. But, at the same time, it would be cool to try using a Gemstone and have FAMIX be compatible with it (that should not be hard).

Cheers,
Doru


On Tue, Aug 20, 2013 at 11:31 AM, Fabrizio Perin <fabrizio.perin@gmail.com>wrote:
Performace is always glad to have but if you cannot do your analyses in the first place because you run out of memory, than it became not a problem. I don't think FUEL is an option in my case, in the sense that with a DB you can fetch a bunch of rows at the time and so you can have your data while keeping the memory cosumption manageable. With FUEL I will need to deserialize all and than do the search. FUEL could help to set up a filesystem DB and so the DBMS can use FUEL to quickly serialize and deserialize objects. On that matter, I would rather prefer to use an existing persistent framework and not to build one from scratch.
 
thanks,
Fabrizio

2013/8/20 Diego Lont <diego.lont@delware.nl>
Hi Fabrizio,

The focus of a database is persistency, not performance of large datasets, so this will probably not help you.

So I would suggest the following directions for a solution:
Use a more memory efficient model than FAMIX (or improve the memory consumption of this model)
Export chuncks of data using FUEL
Link several Moose images that share memory
or Link a Moose image to a gemstone to store the data and do the processing.

Regards,
Diego

On Aug 20, 2013, at 10:51 AM, Fabrizio Perin wrote:

Hi Stef,
How to store the elements on the DB I think will depend on which DBMS you use. With a, e.g., a ORDBMS, we can replicate exactly the structure of the MooseModel within the DB. In my mind I will have a MoosePersistentModel object which hold a reference to the MooseModel stored into the DB and that translate all the operations you can do to search, add, remove and modify an entity in executable SQL and send it to the DB. It sounds really ambitious, but I think I will realize soon after I will start the development if this idea can work or not.
 
Now I just need to identify which DBMS to use and I should decide which persistent framework in Pharo to use. I was thinking at Glorp (with a Postgres DB behind) or at Magma, although I never used neither of them. do you think that they would be suitale for my purpose? Do you have any other candidate to propose? Do you know if there is some nice "getting start documentation" for Magma and Glorp?
 
Thanks a lot,
Fabrizio
 
 
2013/8/19 Stéphane Ducasse <stephane.ducasse@inria.fr>
HI fabrizio

may be you should ask in the pharo mailing-list.
Now the problem to me is how to persist a graph of pointers.

In early version of Moose long time ago there were no pointers to methods, class….but id
So all the code was full of

FAMIXMethod>>msClass
        Model entityWithId: self msClassId


and you could easily plug a stupid DB behind.
Then we decided to use pointers.

But now to me this is not clear how we can save/load part of a large graph.


stef

> Hi,
> I will soon need to analyze quite some java code at once and I'm already sure that one Moose image will not be enough for all that code. Therefore I would like to try to persist the model on a database. Do you have any pointer to a possible persistence manager/OODBMS/RODBMS to use for that purpose?
>
> Thanks in advance,
> Fabrizio
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> Moose-dev@iam.unibe.ch
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