Selecting posts by title

I have the following code in a custom page:

<?php $catposts=get_posts'category=3&numberposts=-1&orderby=date&order=desc'); ?>

<?php foreach($catposts as $single): ?>
		....Do something
<?php   endforeach; ?>

Problem is that on a large post amount, an “out of memory” error is issued; moreover, I just need some first tenth records to be displayed.
So I have added a filter in functions.php, that filters the recordset by post title:

function arabunu ()
{
global $wpdb;
$sorgu= "AND $wpdb->posts.post_status='publish' AND $wpdb->posts.post_type='post' AND $wpdb->posts.post_title LIKE 'BLABLABLA%'";
return $sorgu;
}

inserting the add filter before the query:

<?php add_filter('posts_where', 'arabunu');?>
<?php $catposts=get_posts ('category=3&numberposts=100&orderby=date&order=desc'); ?>

Unfortunatelly the filter is not applied. Any help?