WP_Importer::get_imported_posts

	public function get_imported_posts( $importer_name, $bid ) {
		global $wpdb;

		$hashtable = array();

		$limit  = 100;
		$offset = 0;

		// Grab all posts in chunks.
		do {
			$meta_key = $importer_name . '_' . $bid . '_permalink';
			$sql      = $wpdb->prepare( "SELECT post_id, meta_value FROM $wpdb->postmeta WHERE meta_key = %s LIMIT %d,%d", $meta_key, $offset, $limit );
			$results  = $wpdb->get_results( $sql );

			// Increment offset.
			$offset = ( $limit + $offset );

			if ( ! empty( $results ) ) {
				foreach ( $results as $r ) {
					// Set permalinks into array.
					$hashtable[ $r->meta_value ] = intval( $r->post_id );
				}
			}
		} while ( count( $results ) == $limit );

		// Unset to save memory.
		unset( $results, $r );

		return $hashtable;
	}