Re: Core Data performance [Re: Knowing when a NSArrayController is ready]
Re: Core Data performance [Re: Knowing when a NSArrayController is ready]
- Subject: Re: Core Data performance [Re: Knowing when a NSArrayController is ready]
- From: Dave Fernandes <email@hidden>
- Date: Mon, 26 Jan 2009 23:53:04 -0500
I don't mean to hijack this thread, but I have had a related (?)
problem where a transient String attribute is derived from a
persistent Binary attributed (an archived NSAttributedString). When
my NSTableView sorts on this column, and I modify a managed object
displayed in the table, I get an error in the console:
2009-01-26 23:31:53.039 MyApp[414] *** NSRunLoop ignoring exception
'unresolved keypath: referenceString' that raised during posting of
delayed perform with target 15f7e2e0 and selector 'invokeWithTarget:
The table view, however, *is* able to sort on this attribute when I
click the column header. Is sorting on transient attributes not fully
supported?
Dave
On Jan 26, 2009, at 5:19 PM, Ben Trumbull wrote:
On Jan 26, 2009, at 2:09 PM, email@hidden wrote:
I was wondering about this - especially as I am occasionally
getting a curious EXC_BAD_ACCESS when rebuilding my NSAttributed
string (but that's another post).
To me appear that there are 3 ways to do this:
1. make the string rep after the fetch.
2. cache it in the db as you say.
3. use an NSValueTransformer in the binding.
Also, don't underestimate the power of writing your own custom
NSValueTransformer. The default one used by transformable
attributes is NSKeyedArchiver, but while flexible and powerful, it
can be a bit slow for very small items.
The RTFD is more or less static so maybe caching it in the db is
the simplest and has the same memory footprint as the build on
fetch approach.
Caching in the db will provide a much better in memory footprint,
at the expense of more disk use, and potentially slower saves.
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