Core Data performance (was: Newbie Help understanding Core Data)
Core Data performance (was: Newbie Help understanding Core Data)
- Subject: Core Data performance (was: Newbie Help understanding Core Data)
- From: Charilaos Skiadas <email@hidden>
- Date: Thu, 28 Jul 2005 14:55:18 -0500
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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