Object identity

[Florian Minjat]

I have another question : if I ask magma for an object Player which 
references others Players in its Letters, will magma deserialize all 
the referenced players ?
If it is the case, is there a way to ask for an 'half-deserialization' 
? By that I mean for example getting the referenced Players with all 
their primitive objects but no referenced object ? Otherwise I will 
need to seriously rethink the Mailbox/Letter model of my application.

Florian


Chris Muller wrote:
> Hi Florian, this is an interesting problem.
> 
> First to answer your question, Magma identifies an object as already
> in the repository if it has a "permanent" oid.  This is an oid range
> between MaOidCalculator #firstUserObjectOid and #lastUserObjectOid.
> The #hash of an object never comes into play to determine this, or
> anything in Magma for that matter.
> 
> One way to get your large object-model into Magma would be to change
> the method MaObjectBuffer>>#ensureSpaceFor: to allow more than 10
> megabyte serializations.  I only suggest this only because it is an
> arbitrary limit and it looks like your model is right there just over
> the limit.  Change it to 50-meg on the fastest computer you have, It
> should work.  Submit the commit and let it run all night.
> 
> Another option would be to temporarily change your Players to
> reference the other players only logically; by some temporary id or
> something.  Once you get them loaded into Magma, then reset the
> references back to the actual objects.
> 
> Note #maTransientVariables is available to implement on Player so it
> will not serialize those variables, so you could actually ADD a new
> logical reference, if necessary, and make the hard player reference
> transient (temporarily).
> 
> Please let me know if these ideas are feasible.
> 
> - Chris
> 
> 
> On 6/10/07, Florian Minjat <florian.minjat at emn.fr> wrote:
>> Hi,
>>    I am trying to transfer a big object hierarchy to Magma : 110100
>> objects in 9004144 bytes.
>>    The basic structure is composed of ~70 Players with a lot of stuff
>> inside. Each players can have some Letters which references other
>> Players as sender or recipients.
>>    The problem is that I can't submit one player to an empty Magma
>> repository without letting Magma insert all the references Players.
>> And the resulting transaction is too big, causing an error. So I
>> separated all the Letters from the Players, inserted the players
>> (~50min) and then tried to insert the Letters. But I close the
>> connection to the magma repository between the two, so Magma tried
>> again to load all the references Players.
>>    So here is my question : how does Magma identify a given object as
>> already inside a repository ? Does it compare the hash of the objects
>> and I just need to redefine the hash method of Players ?
>>    Each try is quite long so I would like to understand a little more
>> of the inner mechanisms of Magma instead of trying numerous times.
>>
>> Florian
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>