diff --git a/include/Photo.php b/include/Photo.php
index 3ab374bd0b..e734fed89a 100644
--- a/include/Photo.php
+++ b/include/Photo.php
@@ -1065,6 +1065,16 @@ function store_photo($a, $uid, $imagedata = "", $url = "") {
 	return($image);
 }
 
+/**
+ * @brief Fetch the photo albums that are available for a viewer
+ *
+ * The query in this function is cost intensive, so it is cached.
+ *
+ * @param int $uid User id of the photos
+ * @param bool $update Update the cache
+ *
+ * @return array Returns array of the photo albums
+ */
 function photo_albums($uid, $update = false) {
 	$sql_extra = permissions_sql($uid);
 
@@ -1073,7 +1083,7 @@ function photo_albums($uid, $update = false) {
 	if (is_null($albums) OR $update) {
 		/// @todo This query needs to be renewed. It is really slow
 		// At this time we just store the data in the cache
-		$albums = qu("SELECT count(distinct `resource-id`) AS `total`, `album`
+		$albums = qu("SELECT COUNT(DISTINCT `resource-id`) AS `total`, `album`
 			FROM `photo` USE INDEX (`uid_album_created`)
 			WHERE `uid` = %d  AND `album` != '%s' AND `album` != '%s' $sql_extra
 			GROUP BY `album` ORDER BY `created` DESC",
diff --git a/include/dbstructure.php b/include/dbstructure.php
index 3d14615327..3826716c54 100644
--- a/include/dbstructure.php
+++ b/include/dbstructure.php
@@ -587,6 +587,7 @@ function db_definition($charset) {
 					),
 			"indexes" => array(
 					"PRIMARY" => array("id"),
+					"cmd_item_contact" => array("UNIQUE", "cmd", "item", "contact"),
 					)
 			);
 	$database["event"] = array(
diff --git a/include/socgraph.php b/include/socgraph.php
index e1b5cdbf9a..349869c406 100644
--- a/include/socgraph.php
+++ b/include/socgraph.php
@@ -1115,7 +1115,7 @@ function suggestion_query($uid, $start = 0, $limit = 80) {
 		intval($limit)
 	);
 
-	if(count($r) && count($r) >= ($limit -1)) {
+	if (count($r) && count($r) >= ($limit -1)) {
 		Cache::set("suggestion_query:".$uid.":".$start.":".$limit, $r, CACHE_FIVE_MINUTES);
 		return $r;
 	}
diff --git a/include/threads.php b/include/threads.php
index a487d6e01f..79340ab2cb 100644
--- a/include/threads.php
+++ b/include/threads.php
@@ -22,6 +22,15 @@ function add_thread($itemid, $onlyshadow = false) {
 	}
 }
 
+/**
+ * @brief Add a shadow entry for a given item id
+ *
+ * We store every public item entry additionally with the user id "0".
+ * This is used for the community page and for the search.
+ * It is planned that in the future we will store public item entries only once.
+ *
+ * @param integer $itemid Item ID that should be added
+ */
 function add_shadow_thread($itemid) {
 	$items = q("SELECT `uid`, `wall`, `private`, `moderated`, `visible`, `contact-id`, `deleted`, `network`
 		FROM `item` WHERE `id` = %d AND (`parent` = %d OR `parent` = 0) LIMIT 1", intval($itemid), intval($itemid));