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Re: Cocoa bindings performance
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Re: Cocoa bindings performance


  • Subject: Re: Cocoa bindings performance
  • From: Niels Meersschaert <email@hidden>
  • Date: Fri, 7 Apr 2006 15:07:21 -0400

That's a good resource that I've looked at, but my question is why is there a difference in performance accomplishing the same lookup. In my document class' readFromUrl method I added some code that requests every instance of the entity in order to get the attribute value for summing. I expect the same is occurring with the NSArrayController when I have my code disabled. However, in my testing, the batch I do in the readFromURL method takes less than a second vs several minutes thru the NSArrayController's binding. Is NSArrayController's implementation for retrieving Entity objects different to explain the performance differential?

On Apr 7, 2006, at 2:34 PM, mmalcolm crawford wrote:


On Apr 7, 2006, at 11:26 AM, Niels Meersschaert wrote:

After saving a document that had about 3000 entities, I close it. When I reopen the document, the GUI shows the spinning beachball for several minutes. I've put in logging to determine the array controller is getting valueForKey for each entity to generate the sum. That's fine & expected, but it takes forever. Here's the rub: In the readFromURL method in my document class, I did the same effective lookup that the array controller is. I got the entity from the context, fetching all objects & then got the sum of the field looping thru all of the entities in the returned array. When I do this, the file loads immediately & the bindings show the correct data for each @sum field. Why the dramatic difference in performance? Is this a bug in NSArrayController or do I need to do the manual lookup in my document class?

<http://developer.apple.com/documentation/Cocoa/Conceptual/CoreData/ Articles/cdPerformance.html#//apple_ref/doc/uid/TP40003468-SW3>


mmalc


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  • Follow-Ups:
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References: 
 >Cocoa bindings performance (From: Niels Meersschaert <email@hidden>)
 >Re: Cocoa bindings performance (From: mmalcolm crawford <email@hidden>)

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