Object identity

[Florian Minjat]

Great ! I knew there were already something like that in Magma.
I will test it soon. It should speed up the listing of the players 
considerably.
Thanks !

Florian

Chris Muller wrote:
> Yes, I think you are asking about ReadStrategy's.  They are crucial to
> getting proper performance out of Magma.  Here is the information
> about ReadStrategy's you must understand:
> 
>  http://wiki.squeak.org/squeak/2638
> 
> 
> On 6/12/07, Florian Minjat <florian.minjat at emn.fr> wrote:
>> 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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>> >> Magma at lists.squeakfoundation.org
>> >> http://lists.squeakfoundation.org/mailman/listinfo/magma
>> >>
>> >
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