Magma with style

Fri Dec 10 12:58:06 UTC 2010

On Thu, Dec 9, 2010 at 10:59 PM, Chris Muller <ma.chris.m at gmail.com> wrote:

> Yes, I'm not surprised that takes 3 minutes.  The first problem is
> that you are using an invalid operator in your where.  You must use
> "equals:", not "=".  But the bigger problem is the design.  There is
> overhead to using #where:, especially when using a disjuction or
> sorting or eliminating duplicates.  End-user search and querying is
> the primary use-case for the #where: operations, not using Magma as a
> RDBMS to "look-up" single objects by a key value.

Yes, I don't need that look up when I navigate or use my model but in this
case I'm doing a bulk load so I don't if I can avoid the look-up by a key.

>  The right
> collection for that job is MagmaPreallocatedDictionary, which can be
> large (millions) and still provide very fast #at: access to one object
> at a time.  I do not recommend MagmaDictionary or MagmaSet where
> performance is at all concerned.  For that reason these collections
> really deserve to be deprecated and deleted from Magma.
>

Well to know, I'm going to try it with MagmaPreallocatedDictionary.

>
> The right way to use Magma is to do things as object-oriented as
> possible, and only rely on MagmaCollections for applying
> value-indexing to the objects.  Is documentNumber extrinsic to the
> system, or is it a relational pointer to a Document object?
>

For now, documentNumber is a vi of customer (just aString) but it could be
anObject in other iteration. Maybe is a good moment to reify it to a
Document object (i need find a good name for this class) with document
number and sex variables instance because I need it for the key of
MagmaPreallocatedDictionary since document numbers (in Argentine) aren't
unique. So, I need document number and sex to find a customer.

>
> Regards,
>   Chris
>

Thanks,
Facu

>
>
>
> On Thu, Dec 9, 2010 at 5:47 PM, Facundo Vozzi <facundov79 at gmail.com>
> wrote:
> > Now I'm getting a performance problem.
> > I'm bulk loading transactions in sets (from a file) of 1250. Each of one
> has
> > references to 3 objects, 3 numbers and 2 dates.
> > When I test it without setting the customer it take to me 614
> milliseconds
> > to create the 1250 instances but if I look up for each client according
> to
> > the client code it take to me 204158 milliseconds (3.40 minutes).
> > Customers is a MagmaCollection and this is the method of the message that
> > I'm sending 1250 times:
> > customerAtDocumentNumber: unString sex: otroString
> > "Devuelve un invividuo o una organizacion dependiendo de si unString
> > corresponde a un número de documento o a un número de cuit. NOTA: se debe
> > tener en cuenta el sexo por existir números de dni repetidos entre
> varones y
> > mujeres."
> > | aFewCustomers |
> > aFewCustomers := self customers where: [ :each | (each documentNumber =
> > unString)].
> > ^customers detect: [:each | each documentNumber = unString and: [each sex
> =
> > otroString]] ifNone: []
> >
> >
> > Customers has an index on documentNumber. Now I go to profile it but I
> need
> > to find how to do it in Pharo.
> > I thing that I can switch customers from MagmaCollection to
> MagmaDictionary
> > and set the document number + sex how the key. What do you think?
> > See you,
> > Facu
> >
> > On Thu, Dec 9, 2010 at 7:36 PM, Facundo Vozzi <facundov79 at gmail.com>
> wrote:
> >>>
> >>>
> >>> If you do a copy, then you will be creating multiple instances of
> >>> various "system entities", which I'm guessing don't want to do; you
> >>> would rather have just one instance, referenced from multiple
> >>> transactions, right?
> >>
> >> Yes, you're right I don't want multiple instances.
> >>>
> >>> So all you need to do is just look-up the *equivalent* Code in session
> >>> which is doing the loading.  It will be the one identical instance in
> >>> the repository.
> >>
> >> Yes, to do that I'm passing the session which is doing the loading by
> >> argument.  But I think that my error here is that I'm implementing the
> >> protocol to get one entitiy instance by code or name on the Entity class
> >> side. I think is
> >> better implement it, by example #clientOfCode: aCode, in my system
> >> instance
> >> which is the root of each session. In this manner I don't need pass the
> >> user session by argument. I think that my traditional database mapping
> >> thinking betrayed me
> >>>
> >>> But yes, this is one of the use-cases for which FP's were invented, it
> >>> can be a more elegant solution, especially if the number of Codes is
> >>> always changing or increasing.  See
> >>> MagmaTestCase>>#testForwardingProxy.
> >>
> >> Yes, I will see it right now.
> >> Facu
> >>
> >>>
> >>>  - Chris
> >>>
> >>>
> >>> > Thanks for your help,
> >>> > Facu
> >>> >
> >>> > On Thu, Dec 9, 2010 at 4:35 PM, Chris Muller <asqueaker at gmail.com>
> >>> > wrote:
> >>> >>
> >>> >> I'm not sure I fully understand the context, but a third option
> might
> >>> >> be to use ForwardingProxies.  Especially if the shared objects can
> be
> >>> >> updated by only one session (like a batch updater, for example).
>  Then
> >>> >> every other (user client) session will share the same instances in
> >>> >> memory.
> >>> >>
> >>> >> HTH,
> >>> >>  Chris
> >>> >>
> >>> >> On Wed, Dec 8, 2010 at 1:13 PM, Facundo Vozzi <facundov79 at gmail.com
> >
> >>> >> wrote:
> >>> >> > Hi all,
> >>> >> > I'm refactoring my code and I found that I have two ways to do the
> >>> >> > same
> >>> >> > in
> >>> >> > distint parts of my system.
> >>> >> > 1) Entity class >> atCode: aCode
> >>> >> > "Answer the receiver instance with code equal to aCode or evaluate
> >>> >> > aBlock if
> >>> >> > it doesn't exists."
> >>> >> >        ^(self all detect: [:one | one code = aCode]) copy
> >>> >> > or
> >>> >> > 2) Entity class>> atCode: aCode inSession: anUserSession
> >>> >> > "Answer the receiver instance with code equal to aCode or evaluate
> >>> >> > aBlock if
> >>> >> > it doesn't exists."
> >>> >> >
> >>> >> >        ^(self allInSession: anUserSession) detect: [:one | one
> code
> >>> >> > =
> >>> >> > aCode]
> >>> >> > The difference is that 1 is using the shared session so I need
> copy
> >>> >> > the
> >>> >> > object to be used (referenced by other object) on anUserSession.
> The
> >>> >> > uggly
> >>> >> > of 2 is that I have to pass anUserSession as argument.
> >>> >> > Either way works well, is really the same?
> >>> >> > Thanks in advance,
> >>> >> > Facu
> >>> >> > (*) I eliminate aBlock for absent elements for this example
> >>> >> > _______________________________________________
> >>> >> > Magma mailing list
> >>> >> > Magma at lists.squeakfoundation.org
> >>> >> > http://lists.squeakfoundation.org/mailman/listinfo/magma
> >>> >> >
> >>> >> >
> >>> >
> >>> >
> >>
> >
> >
>
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