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Core Data performance (was: Newbie Help understanding Core Data)



On Jul 28, 2005, at 11:40 AM, SA Dev wrote:


Well, no, it neither floats nor carries planes. HOWEVER ...

Just to clarify, I meant that as a joke of course.
With Core Data, there are a lot more messages being sent through several more layers. For simpler data models, it's inevitable that there'd be more messages being sent (valueForKey, etc). For a simple, flat list (take a very basic "Notes" app for example, that has only "noteDescription" and "completed"). With Bindings, a lot of messages are going back and forth to keep the model in sync with the UI. But what about behind the scenes? With Core Data, you're loading a model, then asking the managed object context and the persistent store coordinator to get every one of these objects to display their only two properties in a table anyway.

Clearly more actual obj-c messages are being sent around to do all that than would be sent to simply read in an array of dict objects from a file and hand it to an array controller.

So if I understand what you are saying, the bindings messages would have pretty much had to be there one way or another, while the Core Data messages are indeed an extra layer. I guess what I am really wondering is, is the hit of all those messages significant compared to the simplicity that Core Data offers. i.e. has anyone measured the performance of the same data structure using Core Data and not using Core Data, and seen if in practical terms there really is a difference?


One can probably make the argument that, given specific data structure, one could device some clever ways of manually handling it, that would save a lot of time at runtime, in some cases, so I can certainly see specialized cases where not using Core Data might be preferable, at the expense of writing some potentially tricky code,

So again my question, and that's really my final question on this, has anyone (maybe Apple?) done measurements to compare a generic Core Data app versus the corresponding app in a non-Core Data way, and compared the runtime performance of the two?

Of course, as you mentioned, there are cases that Core Data is not at the moment capable of handling, and cases where it would really be simpler to not use Core Data at all.

On a completely unrelated question, can someone offer any explanation why if I go to cocoabuilder.com, and search for "Newbie Help understanding", nothing comes up, while there is clearly a thread with that name???

Haris


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References: 
 >Newbie Help understanding Core Data (From: Vince Ackerman <email@hidden>)
 >Re: Newbie Help understanding Core Data (From: Charilaos Skiadas <email@hidden>)
 >Re: Newbie Help understanding Core Data (From: SA Dev <email@hidden>)
 >Re: Newbie Help understanding Core Data (From: Charilaos Skiadas <email@hidden>)
 >Re: Newbie Help understanding Core Data (From: SA Dev <email@hidden>)



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