[misc] Add a vastly more efficient way to display random photos.

CHANGES

@@ -34,6 +34,7 @@ For further information about Photo Organizer, see its web site at:
  [misc] Migrate more queries to take advantage of memcache.
  [fix]  Allow guests/etc to see technical image details. 
  [misc] Consolidated photo and version import into one function.
+ [misc] Added a vastly more efficient way of fetching random photos.
 
 2.36.1 (September 27, 2008)
 

src/include/site.php

@@ -584,8 +584,11 @@ function site_display_photo($database, $identifier, $framed, $version = FALSE) {
 }
 
 function site_get_photos($database, $type, $identifier, $num_of_photos, $order) {
-  $sql_extra_tables = array();
+  global $po_user;
+  global $passwords;
 
+  $sql_extra_tables = array();
+  
   switch ($type) {
   case "photo":
     $parts = explode(":", $identifier);
@@ -599,7 +602,12 @@ function site_get_photos($database, $type, $identifier, $num_of_photos, $order)
     } 
     break;
   case "user":
-    $sql_photo_selector = "photo.users = '$identifier' and photo_version.master = 't' ";
+    if ($order == 21) {
+      $sql_photo_selector = "photo.identifier in (select * from get_random_photos($num_of_photos, $po_user[id], '{".$passwords."}', $identifier)) and photo_version.master = 't'";
+      $order = 0;
+    } else {
+      $sql_photo_selector = "photo.users = '$identifier' and photo_version.master = 't' ";
+    }
     break;
   case "album":
     $sql_photo_selector = "photo_version.identifier = album_content.version and photo.identifier = album_content.photo and album_content.album=".$identifier;

src/sql/PENDING

@@ -2,6 +2,39 @@
 -- v2.3X to XXXX patch  (Unmerged stuff)
 ----------------------------------------------------------
 
+CREATE OR REPLACE FUNCTION get_random_photos(integer, integer, character varying[], integer) RETURNS SETOF integer AS '
+DECLARE num_rows alias for $1;
+	viewer_id alias for $2;
+	passwd_list alias for $3;
+	user_id alias for $4;
+	xmax INT;
+	pick INT;
+	matchid INT;
+	safety INT = 0;
+	rows INT = 0;
+BEGIN 
+      select last_value from photo_id_sequence into xmax;
+      LOOP
+	    EXIT WHEN rows >= num_rows;
+
+            SELECT CEIL(xmax * RANDOM()) INTO pick;
+	    IF user_id > 0 THEN
+	    	    SELECT identifier FROM photo where identifier = pick and users = user_id and can_access_photo(identifier, viewer_id, passwd_list) INTO matchid;
+            ELSE
+	    	    SELECT identifier FROM photo where identifier = pick and can_access_photo(identifier, viewer_id, passwd_list) INTO matchid;
+	    END IF;
+	    IF matchid IS NOT NULL THEN
+	       rows = rows + 1;
+	       RETURN NEXT matchid; 
+            END IF;
+
+	    safety = safety + 1;	
+	    EXIT WHEN safety > 10000;
+      END LOOP;
+      RETURN;
+END;
+' LANGUAGE plpgsql;
+
 --------------------------------- DO NOT APPLY BELOW THIS LINE 
 
 alter table album add column parent_folder references folder(identifier);

src/user.php

@@ -105,6 +105,8 @@ if (($owner_id == 0) || ($owner_type < PO_USER_TYPE_CLIENT)) {
       display_clients($database, $po_user['id'], $auth_handle);
     }
     display_protected_photographers($database, $po_user['id']);
+
+    //    site_display_top_photos($database, 'user', $po_user['id'], 20, FALSE);
   } else {
     if ($po_user['id']) {
       $client = pg_fetch_row(pg_query($database, "select identifier from client where users=$po_user[id] and client=$owner_id"));
@@ -147,7 +149,8 @@ if (($owner_id == 0) || ($owner_type < PO_USER_TYPE_CLIENT)) {
       }
     }
   }
- }
+  site_display_random_photos($database, 'user', $po_user['id'], 10, FALSE);
+}
 
 site_footer($database);
 site_epilog($database);