Implementing Spotlight feature using NSMetaDataQuery and NStableView Data Source Method

Question

I have implemented spotlight feature in my project using NSMetadataQuery. On receiving NSMetadataQueryDidFinishGatheringNotification Notification I am calling reloadData method of tableView method after formatting the NSMetadataItem of NSMetadataQuery. I am facing below two issues.

1. [query startQuery] is taking too much time when there is huge data in mac.
2. Not getting NSMetadataQueryDidUpdateNotification;

Search is fast when I ma using NSArrayController instead of NStableViewDataSource and binding it with query.results. As I need to format the NSMetadataItem so i can't use it.

Can anyone answer how to receive batch notification for better performance of NSMetaDataQuery. or any other way to improve the performance of [query startQuery]

Below is code which I have implemented.

- (void)initiateSearch:(NSString *)seString
{
    self.metadataSearch=[[[NSMetadataQuery alloc] init] autorelease];

    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(queryDidUpdatesfsdf:)
                                                 name:NSMetadataQueryDidUpdateNotification
                                               object:metadataSearch];

    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(initalGatherComplete:)
                                                 name:NSMetadataQueryDidFinishGatheringNotification
                                               object:metadataSearch];

      NSArray *terms = [seString componentsSeparatedByString:@","];
    NSMutableArray  *pridicateArray = [NSMutableArray array];
    NSPredicate *searchPredicate;
    for(NSString *term in terms) {
        if([term length] == 0)
        {
            continue;
        }
        NSString *trimmedString = [[NSString alloc] initWithFormat:@"*%@*",[term stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]]];
        NSPredicate *p = [NSPredicate predicateWithFormat:@"(kMDItemFSName like[cd] %@)",trimmedString];
        [pridicateArray addObject:p];
        [trimmedString release];

    }

    if ([pridicateArray count] == 1) {
        searchPredicate= [pridicateArray objectAtIndex:0];
    }
    else
    {
        searchPredicate = [NSCompoundPredicate orPredicateWithSubpredicates:pridicateArray];
    }
    [metadataSearch setPredicate:searchPredicate];

    NSArray *searchScopes;
    searchScopes=[NSArray arrayWithObjects:NSMetadataQueryUserHomeScope,nil];
    [metadataSearch setSearchScopes:searchScopes];

    NSSortDescriptor *sortKeys=[[[NSSortDescriptor alloc] initWithKey:(id)kMDItemDisplayName
                                                            ascending:YES] autorelease] ;
    [metadataSearch setSortDescriptors:[NSArray arrayWithObject:sortKeys]];

    [metadataSearch setNotificationBatchingInterval:5.0];

    [metadataSearch startQuery];
}

- (void)queryDidUpdatesfsdf:sender;
{
    NSLog(@"A data batch has been received");
}


- (void)initalGatherComplete:sender;
{
    [metadataSearch stopQuery];

    p_Thread = [[NSThread alloc] initWithTarget:self selector:@selector(dosome:) object:metadataSearch];

    [p_Thread start];

    [[NSNotificationCenter defaultCenter] removeObserver:self
                                                    name:NSMetadataQueryDidUpdateNotification
                                                  object:metadataSearch];
    [[NSNotificationCenter defaultCenter] removeObserver:self
                                                    name:NSMetadataQueryDidFinishGatheringNotification
                                                  object:metadataSearch];

}

-(void)dosome: (NSMetadataQuery *)metadataresult
{
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"MM/dd/yyyy HH:mm:ss"];

    fileListArray = [[NSMutableArray alloc] init];
    [fileListArray removeAllObjects];
    NSUInteger i=0;
    for (i=0; (i < [metadataresult resultCount] && ![p_Thread isCancelled]); i++) {
        NSMetadataItem *theResult = [metadataresult resultAtIndex:i];
        NSString *displayName = [theResult valueForAttribute:(NSString *)kMDItemFSName];
        NSString *displayPath = [theResult valueForAttribute:(NSString *)kMDItemPath];
        NSString *fileSize = [theResult valueForAttribute:(NSString *)kMDItemFSSize];


        FileList *fileList = [[FileList alloc] init];
        [fileList setName:displayName];
        [fileList setIsChecked:NO];
        [fileList setPath:displayPath];
        [fileList setLastModified:[dateFormatter stringFromDate:[theResult valueForAttribute:(NSString *)kMDItemContentModificationDate]]];
        [fileList setFileSize:[IBUtility formatedFileSizeForOutlineView:fileSize]];
        [fileList setMSize:[fileSize longLongValue]];
        [[self fileListArray] addObject:fileList];

        if (i%50 == 0  && ![p_Thread isCancelled]) {
            [searhFinderTableView performSelectorOnMainThread:@selector(reloadData) withObject:Nil waitUntilDone:YES];
        }
    }
    self.metadataSearch=nil;

    if ([[self fileListArray] count] == 0) {
        [mSearchingLabel setStringValue:@"Items not found"];

        NSRect textFieldFrame = [mSearchingLabel frame];

        [mSearchingLabel setFrame:NSMakeRect(mContinuousProgress.frame.origin.x,textFieldFrame.origin.y, textFieldFrame.size.width,textFieldFrame.size.height)];
    }
    else if(![p_Thread isCancelled])
    {
        [searhFinderTableView performSelectorOnMainThread:@selector(reloadData) withObject:Nil waitUntilDone:YES];
        [mSearchingLabel setHidden:YES];
    }

    [mContinuousProgress stopAnimation:self];
    [dateFormatter release];

    [pool release];

}
- (NSInteger)numberOfRowsInTableView:(NSTableView *)aTableView
{
    return [fileListArray count];

}


- (id)tableView:(NSTableView *)aTableView objectValueForTableColumn:(NSTableColumn *)aTableColumn row:(NSInteger)rowIndex
{
    FileList *fileList = [fileListArray objectAtIndex:rowIndex];

    if ([[aTableColumn identifier] isEqualToString:@"filePath"])
    {
        return [fileList valueForKey:@"path"];
    }
    else if([[aTableColumn identifier] isEqualToString:@"isSelected"])
    {
        return [NSNumber numberWithBool:fileList.isChecked];
    }
    else if([[aTableColumn identifier] isEqualToString:@"fileSize"])
    {
        return [fileList valueForKey:@"fileSize"];
    }
    else if([[aTableColumn identifier] isEqualToString:@"lastModified"])
    {
        return [fileList valueForKey:@"lastModified"];
    }
    return nil;
}