diff --git a/include/functions_search.inc.php b/include/functions_search.inc.php
index 2d6ba1bcc..124e2fcb6 100644
--- a/include/functions_search.inc.php
+++ b/include/functions_search.inc.php
@@ -616,6 +616,74 @@ SELECT
   );
 }
 
+/**
+ * Returns the SQL WHERE clause to be used to build filter values
+ *
+ * @since 15
+ *
+ * @param string $filter_name
+ *
+ * @return string
+ */
+function get_clause_for_filter($filter_name)
+{
+  global $page;
+
+  $other_filters_items = get_items_for_filter($filter_name);
+  if (false === $other_filters_items)
+  {
+    return '1=1'.$page['search_details']['forbidden'];
+  }
+
+  return 'image_id IN ('.implode(',', $other_filters_items).')';
+}
+
+/**
+ * Returns the list of items (image_ids) to be used to build filter values
+ * for a given filter. Depends on the other filters. Use a cache to avoid
+ * computing the same large array_intersect several times.
+ *
+ * @since 15
+ *
+ * @param string $filter_name
+ *
+ * @return array of image_ids (or false)
+ */
+function get_items_for_filter($filter_name)
+{
+  global $page, $logger;
+
+  $other_filters = array_diff(array_keys($page['search_details']['image_ids_for_filter']), array($filter_name));
+
+  if (empty($other_filters))
+  {
+    return false;
+  }
+
+  $cache_key = md5(implode(',', $other_filters));
+
+  if (!isset($page['search_details'][__FUNCTION__][$cache_key]))
+  {
+    $function_start = get_moment();
+
+    $other_filters_items = $page['search_details']['image_ids_for_filter'][array_shift($other_filters)];
+    foreach ($other_filters as $other_filter)
+    {
+      $other_filters_items = array_intersect($other_filters_items, $page['search_details']['image_ids_for_filter'][$other_filter]);
+    }
+
+    $other_filters_items = array_unique($other_filters_items);
+
+    $debug_msg = '['.__FUNCTION__.'] cache computed for '.(count($other_filters)+1).' other filters';
+    $debug_msg.= ' ('.count($other_filters_items).' items)';
+    $debug_msg.= ', time = '.get_elapsed_time($function_start, get_moment());
+    $logger->debug($debug_msg);
+
+    @$page['search_details'][__FUNCTION__][$cache_key] = $other_filters_items;
+  }
+
+  return $page['search_details'][__FUNCTION__][$cache_key];
+}
 
 
 define('QST_QUOTED',         0x01);
diff --git a/index.php b/index.php
index 05d095f80..968c7adc0 100644
--- a/index.php
+++ b/index.php
@@ -183,7 +183,7 @@ if ( empty($page['is_external']) )
 
     $my_search = get_search_array($page['search']);
 
-    $search_forbidden = get_sql_condition_FandF(
+    $page['search_details']['forbidden'] = get_sql_condition_FandF(
       array(
         'forbidden_categories' => 'category_id',
         'visible_categories' => 'category_id',
@@ -215,16 +215,14 @@ if ( empty($page['is_external']) )
       // TODO calling get_available_tags(), with lots of photos/albums/tags may cost time,
       // we should reuse the result if already executed (for building the menu for example)
 
-      $other_filters = array_diff(array_keys($page['search_details']['image_ids_for_filter']), array('tags'));
-      if (count($other_filters) > 0)
+      $other_filters_items = get_items_for_filter('tags');
+      if (false === $other_filters_items)
+      {
+        $filter_tags = get_available_tags();
+        usort($filter_tags, 'tag_alpha_compare');
+      }
+      else
       {
-        $other_filters_items = $page['search_details']['image_ids_for_filter'][array_shift($other_filters)];
-        foreach ($other_filters as $other_filter)
-        {
-          $other_filters_items = array_intersect($other_filters_items, $page['search_details']['image_ids_for_filter'][$other_filter]);
-        }
-        $other_filters_items = array_unique($other_filters_items);
-
         $filter_tags = get_common_tags($other_filters_items, 0);
 
         // the user may have started a search on 2 or more tags that have no
@@ -238,11 +236,6 @@ if ( empty($page['is_external']) )
           $filter_tags = array_merge(get_available_tags($missing_tag_ids), $filter_tags);
         }
       }
-      else
-      {
-        $filter_tags = get_available_tags();
-        usort($filter_tags, 'tag_alpha_compare');
-      }
 
       $template->assign('TAGS', $filter_tags);
 
@@ -254,22 +247,7 @@ if ( empty($page['is_external']) )
 
     if (isset($my_search['fields']['author']))
     {
-      $other_filters = array_diff(array_keys($page['search_details']['image_ids_for_filter']), array('author'));
-      if (count($other_filters) > 0)
-      {
-        $other_filters_items = $page['search_details']['image_ids_for_filter'][array_shift($other_filters)];
-        foreach ($other_filters as $other_filter)
-        {
-          $other_filters_items = array_intersect($other_filters_items, $page['search_details']['image_ids_for_filter'][$other_filter]);
-        }
-        $other_filters_items = array_unique($other_filters_items);
-
-        $filter_clause = 'image_id IN ('.implode(',', $other_filters_items).')';
-      }
-      else
-      {
-        $filter_clause = '1=1'.$search_forbidden;
-      }
+      $filter_clause = get_clause_for_filter('author');
 
       $query = '
 SELECT
@@ -295,22 +273,7 @@ SELECT
 
     if (isset($my_search['fields']['date_posted']))
     {
-      $other_filters = array_diff(array_keys($page['search_details']['image_ids_for_filter']), array('date_posted'));
-      if (count($other_filters) > 0)
-      {
-        $other_filters_items = $page['search_details']['image_ids_for_filter'][array_shift($other_filters)];
-        foreach ($other_filters as $other_filter)
-        {
-          $other_filters_items = array_intersect($other_filters_items, $page['search_details']['image_ids_for_filter'][$other_filter]);
-        }
-        $other_filters_items = array_unique($other_filters_items);
-
-        $filter_clause = 'image_id IN ('.implode(',', $other_filters_items).')';
-      }
-      else
-      {
-        $filter_clause = '1=1'.$search_forbidden;
-      }
+      $filter_clause = get_clause_for_filter('date_posted');
 
       $query = '
 SELECT
@@ -390,22 +353,7 @@ SELECT
 
     if (isset($my_search['fields']['added_by']))
     {
-      $other_filters = array_diff(array_keys($page['search_details']['image_ids_for_filter']), array('added_by'));
-      if (count($other_filters) > 0)
-      {
-        $other_filters_items = $page['search_details']['image_ids_for_filter'][array_shift($other_filters)];
-        foreach ($other_filters as $other_filter)
-        {
-          $other_filters_items = array_intersect($other_filters_items, $page['search_details']['image_ids_for_filter'][$other_filter]);
-        }
-        $other_filters_items = array_unique($other_filters_items);
-
-        $filter_clause = 'image_id IN ('.implode(',', $other_filters_items).')';
-      }
-      else
-      {
-        $filter_clause = '1=1'.$search_forbidden;
-      }
+      $filter_clause = get_clause_for_filter('added_by');
 
       $query = '
 SELECT
@@ -483,22 +431,7 @@ SELECT
 
     if (isset($my_search['fields']['filetypes']))
     {
-      $other_filters = array_diff(array_keys($page['search_details']['image_ids_for_filter']), array('filetypes'));
-      if (count($other_filters) > 0)
-      {
-        $other_filters_items = $page['search_details']['image_ids_for_filter'][array_shift($other_filters)];
-        foreach ($other_filters as $other_filter)
-        {
-          $other_filters_items = array_intersect($other_filters_items, $page['search_details']['image_ids_for_filter'][$other_filter]);
-        }
-        $other_filters_items = array_unique($other_filters_items);
-
-        $filter_clause = 'image_id IN ('.implode(',', $other_filters_items).')';
-      }
-      else
-      {
-        $filter_clause = '1=1'.$search_forbidden;
-      }
+      $filter_clause = get_clause_for_filter('filetypes');
 
       $query = '
 SELECT
@@ -516,22 +449,7 @@ SELECT
     // For rating
     if (isset($my_search['fields']['ratings']))
     {
-      $other_filters = array_diff(array_keys($page['search_details']['image_ids_for_filter']), array('ratings'));
-      if (count($other_filters) > 0)
-      {
-        $other_filters_items = $page['search_details']['image_ids_for_filter'][array_shift($other_filters)];
-        foreach ($other_filters as $other_filter)
-        {
-          $other_filters_items = array_intersect($other_filters_items, $page['search_details']['image_ids_for_filter'][$other_filter]);
-        }
-        $other_filters_items = array_unique($other_filters_items);
-
-        $filter_clause = 'image_id IN ('.implode(',', $other_filters_items).')';
-      }
-      else
-      {
-        $filter_clause = '1=1'.$search_forbidden;
-      }
+      $filter_clause = get_clause_for_filter('ratings');
 
       $ratings = array_fill(0, 6, 0);
 
@@ -573,22 +491,7 @@ SELECT
     // For filesize
     if (isset($my_search['fields']['filesize_min']) && isset($my_search['fields']['filesize_max']))
     {
-      $other_filters = array_diff(array_keys($page['search_details']['image_ids_for_filter']), array('filesize'));
-      if (count($other_filters) > 0)
-      {
-        $other_filters_items = $page['search_details']['image_ids_for_filter'][array_shift($other_filters)];
-        foreach ($other_filters as $other_filter)
-        {
-          $other_filters_items = array_intersect($other_filters_items, $page['search_details']['image_ids_for_filter'][$other_filter]);
-        }
-        $other_filters_items = array_unique($other_filters_items);
-
-        $filter_clause = 'image_id IN ('.implode(',', $other_filters_items).')';
-      }
-      else
-      {
-        $filter_clause = '1=1'.$search_forbidden;
-      }
+      $filter_clause = get_clause_for_filter('filesize');
 
       $filesizes = array();
       $filesize = array();
@@ -635,22 +538,7 @@ SELECT
     
     if (isset($my_search['fields']['ratios']))
     {
-      $other_filters = array_diff(array_keys($page['search_details']['image_ids_for_filter']), array('ratios'));
-      if (count($other_filters) > 0)
-      {
-        $other_filters_items = $page['search_details']['image_ids_for_filter'][array_shift($other_filters)];
-        foreach ($other_filters as $other_filter)
-        {
-          $other_filters_items = array_intersect($other_filters_items, $page['search_details']['image_ids_for_filter'][$other_filter]);
-        }
-        $other_filters_items = array_unique($other_filters_items);
-
-        $filter_clause = 'image_id IN ('.implode(',', $other_filters_items).')';
-      }
-      else
-      {
-        $filter_clause = '1=1'.$search_forbidden;
-      }
+      $filter_clause = get_clause_for_filter('ratios');
 
       $query = '
 SELECT
@@ -696,22 +584,7 @@ SELECT
 
     if (isset($my_search['fields']['height_min']) and isset($my_search['fields']['height_max']))
     {
-      $other_filters = array_diff(array_keys($page['search_details']['image_ids_for_filter']), array('height'));
-      if (count($other_filters) > 0)
-      {
-        $other_filters_items = $page['search_details']['image_ids_for_filter'][array_shift($other_filters)];
-        foreach ($other_filters as $other_filter)
-        {
-          $other_filters_items = array_intersect($other_filters_items, $page['search_details']['image_ids_for_filter'][$other_filter]);
-        }
-        $other_filters_items = array_unique($other_filters_items);
-
-        $filter_clause = 'image_id IN ('.implode(',', $other_filters_items).')';
-      }
-      else
-      {
-        $filter_clause = '1=1'.$search_forbidden;
-      }
+      $filter_clause = get_clause_for_filter('height');
 
       $query = '
 SELECT
@@ -742,22 +615,7 @@ SELECT
 
     if (isset($my_search['fields']['width_min']) and isset($my_search['fields']['width_max']))
     {
-      $other_filters = array_diff(array_keys($page['search_details']['image_ids_for_filter']), array('width'));
-      if (count($other_filters) > 0)
-      {
-        $other_filters_items = $page['search_details']['image_ids_for_filter'][array_shift($other_filters)];
-        foreach ($other_filters as $other_filter)
-        {
-          $other_filters_items = array_intersect($other_filters_items, $page['search_details']['image_ids_for_filter'][$other_filter]);
-        }
-        $other_filters_items = array_unique($other_filters_items);
-
-        $filter_clause = 'image_id IN ('.implode(',', $other_filters_items).')';
-      }
-      else
-      {
-        $filter_clause = '1=1'.$search_forbidden;
-      }
+      $filter_clause = get_clause_for_filter('width');
 
       $query = '
 SELECT