Re: CoreData fetch is way too slow

FROM : James Hober
DATE : Tue Feb 26 20:22:25 2008

A while back, James Hober wrote:

> I simply changed the predicate from using LIKE to using == and fetch
> time plummeted from 7 seconds to 0.18 seconds.
>
> This is very usable.  I think it is a better user experience to shave
> off the 3.5 seconds of launch time that my previous implementation
> needed in exchange for each query taking 0.18 seconds.
>
> Several of you suggested indexing the attribute I search against.  It
> looks like indexing an attribute is only available in Leopard and for
> now I have to support Tiger.
>
> I will continue to investigate further optimization.


Turns out I really did want to index the Core Data attribute.  Fetch 
time without indexing was still a bit too long, and especially after 
a restart could be more than 3 seconds.  That's not the first 
impression I want to make to a user.

But since I'm doing this on Tiger, I simply used Terminal to navigate 
to the Xcode project folder, typed "sqlite3 MyDBfile.db" and then at 
the sqlite prompt typed "CREATE INDEX ZMYENTITY_ZINPUT_INDEX ON 
ZMYENTITY (ZINPUT);"

(apparently Core Data prefixes 'Z' to your identifiers.)

Now all the fetches seem to be a speedy 0.02 to 0.03 seconds.

Am I in any danger going around Core Data's back this way?

James