On Sat, Feb 13, 2010 at 4:06 AM, Roland King <r...@rols.org> wrote: > That's not a horrible solution, except for the feeling that core data ought > to let you do what you want without having to implement your own UUID cache. > I'm still a bit surprised that a lookup for an object by one attribute is > taking so long, over just 30,000 objects. You do have the uuid attribute > marked as indexed right? > > I found > http://cocoawithlove.com/2008/03/testing-core-data-with-very-big.htmlwhilst > hunting around for some examples of core data with big data sets. > This guy was working on sets of 1 million objects and doing fetches with > indexed properties was taking about 2 seconds, vs non-indexed, 600 seconds. > There are some comments at the bottom from an apple engineer too. >
Hi Roland, Uhmmm probability there is something wrong with my code, because with indexed messageid property it takes a very long time too (I can't see any visible difference, 20k messages took minutes to be completed) Here you will found my simple storage data model: http://img197.imageshack.us/img197/4388/screenshot20100213at111.jpg This is my code: for (NSString *cMessage in messagedata) { NSString *idd = [cMessage headerValueFor:ARTICLE_TAG_ID]; // takes the MESSAGE UUID if ([thegroup articleForID:idd inCtx:ctx] == nil) { // CHECK IF MESSAGE UUID IS ALREADY ON DB MCArticle *c = [MCArticle newArticleWithID:idd context:ctx]; // WE CAN MAKE THE MESSAGE AND ADD IT TO COREDATA // WE WANT TO CHECK FOR PARENT NSString *parentidms = [[[f headerValueFor:ARTICLE_TAG_REFS] reverseOrderedReferences] objectAtIndex:0]; MCArticle *parent = [thegroup articleForID:parentidms inCtx:ctx]; // WE QUERY FOR PARENT UUID if (parent != nil) { // LINK BOTH PARENT AND CHILD } } } ArticleForID:inCtx: method follow (inCtx is required becase these functions works in a multithreading environment) (I've also tried to re-use fetchRequest object but it's not the main problem...) - (MCArticle *) articleForID:(NSString*) _msgid inCtx:(NSManagedObjectContext*) ctx { if (_msgid == nil) return nil; NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init]; [fetchRequest setFetchLimit:1]; [fetchRequest setEntity: [NSEntityDescription entityForName:@"MCArticle" inManagedObjectContext:ctx]]; NSPredicate *predicate = [NSPredicate predicateWithFormat:@"messageid == %@",_msgid]; [fetchRequest setPredicate: predicate]; NSArray *results = [ctx executeFetchRequest:fetchRequest error:nil]; [fetchRequest release]; if ([results count]==0)return nil; return [results objectAtIndex:0]; } Finally the init method for Message object: + (MCArticle *) newArticleWithID:(NSString *) _messageID context:(NSManagedObjectContext *) _context { MCArticle *oj = (MCArticle*)[[NSManagedObject alloc] initWithEntity:[NSEntityDescription entityForName:@"MCArticle" inManagedObjectContext:_context] insertIntoManagedObjectContext:_context]; [oj setValue:_messageID forKey:@"messageid"]; return oj; } _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
