Don't split the main query if there is no limit. This helps avoid ext…

…remely long query strings that could cause segfaults. Allow plugins to control splitting via split_the_query filter. see #20628

git-svn-id: http://core.svn.wordpress.org/trunk@20740 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/query.php

@@ -2626,7 +2626,9 @@ function &get_posts() {
 			return $r;
 		}
 
-		if ( $old_request == $this->request && "$wpdb->posts.*" == $fields ) {
+		$split_the_query = apply_filters( 'split_the_query', ( $old_request == $this->request && "$wpdb->posts.*" == $fields && !empty( $limits) ), $this );
+
+		if ( $split_the_query ) {
 			// First get the IDs and then fill in the objects
 
 			$this->request = "SELECT $found_rows $distinct $wpdb->posts.ID FROM $wpdb->posts $join WHERE 1=1 $where $groupby $orderby $limits";