Re: CoreData: Attr. uniqueness, Multithreading
Re: CoreData: Attr. uniqueness, Multithreading
- Subject: Re: CoreData: Attr. uniqueness, Multithreading
- From: Scott Stevenson <email@hidden>
- Date: Mon, 14 Nov 2005 18:32:50 -0800
On Nov 14, 2005, at 2:59 PM, Marc Monguio wrote:
The first one is perfomance. I have one entity with a path
attribute which I want to be unique. To do so, before I add a new
row into the entity I fetch for that path in the database if
there's not any I add the new row with the path information.
What does the code for the uniqueness check look like?
The firsts inserts are quite fast but as long as the db increases
it's size it's slower and slower.
I've tried to use the undocumented feature shown in this list for
indexing properties (_NSCreateIndex) but it works as slow as
before. Maybe is that I'm not doing in correctly, is it ?
I believe indexes will slow inserts.
The second problem I'm facing right now is that my application uses
one thread to populate the entity with paths and other information.
Meanwhile through the UI users can be able to add more stuff in the
entity. Everytime there's a fetch the applications throws an
exception saying:
Instead of entity do you mean managed object? Not trying to nitpick,
just trying to be clear.
The entity is just the abstract definition of a particular *kind* of
object.
An uncaught exception was raised
2005-11-14 12:52:58.162 Test[16594] _obtainOpenChannel -- NSSQLCore
0x4044750: no database channel is available
2005-11-14 12:52:58.163 Test[16594] *** Uncaught exception:
<NSInternalInconsistencyException> _obtainOpenChannel -- NSSQLCore
0x4044750: no database channel is available
I'm not familiar with this particular error, but how have you setup
your threads? Do you have one context per thread? Are you passing
objectIDs between them?
- Scott
--
http://theocacao.com/
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