Re: Core Data fetch performance
Re: Core Data fetch performance
- Subject: Re: Core Data fetch performance
- From: Mike Abdullah <email@hidden>
- Date: Fri, 16 Nov 2012 11:56:57 +0000
On 12 Nov 2012, at 14:15, Joerg Simon <email@hidden> wrote:
> This summs it up really nicely:
>
> http://wbyoung.tumblr.com/post/27851725562/core-data-growing-pains
>
> Links to radar bug reports are within the blog post.
>
> The conclusion it is not usable does not hold under iOS6, since nested contexts work quite wonderfully there, but it shows problems under iOS5.
>
> Generally if you use performBlock and not performBlockAndWhait and do not use a fetched results controller at all and some other tricks, you can get it working quite well also under iOS5, but actually the code you produce is uglier than doing it manually the "old way" using thread confinment and merge by hand. At least in my experience.
>
> But under iOS6 nested contexts rock!
So to summarise:
- Child contexts synchronously route through their parent to perform fetches. The author thinks this is a mistake; I consider it an expected consequence of the design
- "Making changes into a parent context can be slow" with no mention of a radar or details of any possible fix
- Child contexts in iOS5/OS X 10.7 are pretty buggy when it comes to propogating changes *down* from their parent. This is where iOS 6/OS X 10.8 appears to have improved matters.
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