如何优化基于Core Data的搜索？

Question

如何优化基于Core Data的搜索？

Mos*_*she 5 iphone optimization core-data objective-c ios

我正在尝试在我的应用中实现搜索.有两个核心数据实体,"Tag"和"DvarTorah".标签只有一个字符串."DvarTorah"具有标题,文本内容和一些其他属性.我正试图找出快速搜索它们的最佳方法.该应用程序附带了大约1200个DvarTorah实体,甚至更多的标签.现在,当我的搜索视图控制器调用viewDidLoad时,我加载了一个NSFetchedResultsController.然后,当用户键入搜索框或更改范围时,我调用一个方法,该方法同时接收范围栏值和搜索词,并过滤我的对象数组.这是看起来如何:

- (void) filterArrayWithSearchTerm:(NSString *)searchString andScopeIndex:(NSInteger)scopeIndex{

    if ([searchString isEqualToString:@""]) {
        return;
    }    

    NSMutableArray *unfilteredResults = [[[[self.fetchedResultsController sections] objectAtIndex:0] objects] mutableCopy];

    if (self.filteredArray == nil){
        self.filteredArray = [[[NSMutableArray alloc ] init] autorelease];
    }

    [filteredArray removeAllObjects];

    NSPredicate *predicate = [[[NSPredicate alloc] init] autorelease];

    if (scopeIndex == 0) {
        predicate = [NSPredicate predicateWithFormat:@"dvarTorahTitle CONTAINS[cd] %@", searchString];
    }else if (scopeIndex == 1) {
        predicate = [NSPredicate predicateWithFormat:@"searchableContent CONTAINS[cd] %@", [searchString canonicalString]];            
    }else if (scopeIndex == 2){
        predicate = [NSPredicate predicateWithFormat:@"ANY tags.tagText CONTAINS[cd] %@", searchString];
    }else{
        predicate = [NSPredicate predicateWithFormat:@"(ANY tags.tagText CONTAINS[cd] %@) OR (dvarTorahTitle CONTAINS[cd] %@) OR (searchableContent CONTAINS[cd] %@)", searchString,searchString,searchString];
    }

    for (DvarTorah *dvarTorah in unfilteredResults) {
        if ([predicate evaluateWithObject:dvarTorah]) {
            [self.filteredArray addObject:dvarTorah];
        }
    }

    [unfilteredResults release];
}

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问题是我的搜索方法非常慢.我知道CONTAINS可能是罪魁祸首,但即使存储了内容的规范版本(作为searchableContent)并尝试进一步优化,搜索也非常缓慢.我怎样才能让它更快？

编辑:

基于雅各布的初步建议,这是我的新方法:

    if ([searchString isEqualToString:@""]) {
    return;
}

if (self.filteredArray == nil) {
    self.filteredArray = [[[NSMutableArray alloc ] init] autorelease];
}

[filteredArray removeAllObjects];

NSPredicate *predicate = nil;

if (scopeIndex == 0) {
    predicate = [NSPredicate predicateWithFormat:@"dvarTorahTitle CONTAINS[cd] %@", searchString];
}else if (scopeIndex == 1) {
    predicate = [NSPredicate predicateWithFormat:@"searchableContent CONTAINS[cd] %@", [searchString canonicalString]];            
}else if (scopeIndex == 2){
    predicate = [NSPredicate predicateWithFormat:@"ANY tags.tagText CONTAINS[cd] %@", searchString];
}else{
    predicate = [NSPredicate predicateWithFormat:@"(ANY tags.tagText CONTAINS[cd] %@) OR (dvarTorahTitle CONTAINS[cd] %@) OR (searchableContent CONTAINS[cd] %@)", searchString,searchString,searchString];
}

[self.filteredArray addObjectsFromArray:[[[[[self.fetchedResultsController sections] objectAtIndex:0] objects] mutableCopy] filteredArrayUsingPredicate:predicate]];

}

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EDIT2:

不再复制数组,仍然很慢:

- (void) filterArrayWithSearchTerm:(NSString *)searchString andScopeIndex:(NSInteger)scopeIndex{

    if ([searchString isEqualToString:@""]) {
        return;
    }

    if (self.filteredArray == nil) {
        self.filteredArray = [[[NSMutableArray alloc ] init] autorelease];
    }

    [filteredArray removeAllObjects];

    NSPredicate *predicate = nil;

    if (scopeIndex == 0) {
        predicate = [NSPredicate predicateWithFormat:@"dvarTorahTitle CONTAINS[cd] %@", searchString];
    }else if (scopeIndex == 1) {
        predicate = [NSPredicate predicateWithFormat:@"searchableContent CONTAINS[cd] %@", [searchString canonicalString]];            
    }else if (scopeIndex == 2){
        predicate = [NSPredicate predicateWithFormat:@"ANY tags.tagText CONTAINS[cd] %@", searchString];
    }else{
        predicate = [NSPredicate predicateWithFormat:@"(ANY tags.tagText CONTAINS[cd] %@) OR (dvarTorahTitle CONTAINS[cd] %@) OR (searchableContent CONTAINS[cd] %@)", searchString,searchString,searchString];
    }

    [self.filteredArray addObjectsFromArray:[[[[self.fetchedResultsController sections] objectAtIndex:0] objects] filteredArrayUsingPredicate:predicate]];
}

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