Index: SQL/mssql.initial.sql
===================================================================
--- SQL/mssql.initial.sql	(revision 3e48d2eee1d2af42aa777fd5e461fa570762732e)
+++ SQL/mssql.initial.sql	(revision dcf780a6bd5065ffb0dcc76233b1e5f601e258d2)
@@ -2,5 +2,4 @@
 	[cache_id] [int] IDENTITY (1, 1) NOT NULL ,
 	[user_id] [int] NOT NULL ,
-	[session_id] [varchar] (32) COLLATE Latin1_General_CI_AI NULL ,
 	[cache_key] [varchar] (128) COLLATE Latin1_General_CI_AI NOT NULL ,
 	[created] [datetime] NOT NULL ,
@@ -120,5 +119,4 @@
 ALTER TABLE [dbo].[cache] ADD 
 	CONSTRAINT [DF_cache_user_id] DEFAULT ('0') FOR [user_id],
-	CONSTRAINT [DF_cache_session_id] DEFAULT (null) FOR [session_id],
 	CONSTRAINT [DF_cache_cache_key] DEFAULT ('') FOR [cache_key],
 	CONSTRAINT [DF_cache_created] DEFAULT (getdate()) FOR [created]
@@ -129,7 +127,4 @@
 
  CREATE  INDEX [IX_cache_cache_key] ON [dbo].[cache]([cache_key]) ON [PRIMARY]
-GO
-
- CREATE  INDEX [IX_cache_session_id] ON [dbo].[cache]([session_id]) ON [PRIMARY]
 GO
 
Index: SQL/mysql.initial.sql
===================================================================
--- SQL/mysql.initial.sql	(revision 3e48d2eee1d2af42aa777fd5e461fa570762732e)
+++ SQL/mysql.initial.sql	(revision dcf780a6bd5065ffb0dcc76233b1e5f601e258d2)
@@ -12,5 +12,4 @@
   `cache_id` int(10) unsigned NOT NULL auto_increment,
   `user_id` int(10) unsigned NOT NULL default '0',
-  `session_id` varchar(40) default NULL,
   `cache_key` varchar(128) NOT NULL default '',
   `created` datetime NOT NULL default '0000-00-00 00:00:00',
Index: SQL/mysql.update.sql
===================================================================
--- SQL/mysql.update.sql	(revision 3e48d2eee1d2af42aa777fd5e461fa570762732e)
+++ SQL/mysql.update.sql	(revision dcf780a6bd5065ffb0dcc76233b1e5f601e258d2)
@@ -35,9 +35,6 @@
 
 ALTER TABLE `cache`
-    ADD CONSTRAINT `session_id_fk_cache` FOREIGN KEY (`session_id`)
-    REFERENCES `session`(`sess_id`)
-    ON DELETE CASCADE
-    ON UPDATE CASCADE;
-
+    DROP `session_id`;
+    
 ALTER TABLE `session`
     ADD INDEX `changed_index` (`changed`);
Index: SQL/mysql5.initial.sql
===================================================================
--- SQL/mysql5.initial.sql	(revision 3e48d2eee1d2af42aa777fd5e461fa570762732e)
+++ SQL/mysql5.initial.sql	(revision dcf780a6bd5065ffb0dcc76233b1e5f601e258d2)
@@ -69,5 +69,4 @@
 CREATE TABLE `cache` (
  `cache_id` int(10) UNSIGNED NOT NULL AUTO_INCREMENT,
- `session_id` varchar(40) CHARACTER SET ascii COLLATE ascii_general_ci,
  `cache_key` varchar(128) CHARACTER SET ascii COLLATE ascii_general_ci NOT NULL,
  `created` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
@@ -78,8 +77,4 @@
  CONSTRAINT `user_id_fk_cache` FOREIGN KEY (`user_id`)
    REFERENCES `users`(`user_id`)
-     ON DELETE CASCADE
-     ON UPDATE CASCADE,
- CONSTRAINT `session_id_fk_cache` FOREIGN KEY (`session_id`)
-   REFERENCES `session`(`sess_id`)
      ON DELETE CASCADE
      ON UPDATE CASCADE
Index: SQL/postgres.initial.sql
===================================================================
--- SQL/postgres.initial.sql	(revision 3e48d2eee1d2af42aa777fd5e461fa570762732e)
+++ SQL/postgres.initial.sql	(revision dcf780a6bd5065ffb0dcc76233b1e5f601e258d2)
@@ -130,5 +130,4 @@
     cache_id integer DEFAULT nextval('cache_ids'::text) PRIMARY KEY,
     user_id integer NOT NULL REFERENCES users (user_id) ON DELETE CASCADE ON UPDATE CASCADE,
-    session_id character varying(40) REFERENCES "session" (sess_id) ON DELETE CASCADE ON UPDATE CASCADE,
     cache_key character varying(128) DEFAULT ''::character varying NOT NULL,
     created timestamp with time zone DEFAULT now() NOT NULL,
@@ -137,5 +136,4 @@
 
 CREATE INDEX cache_user_id_idx ON "cache" (user_id, cache_key);
-CREATE INDEX cache_session_id_idx ON "cache" (session_id);
 
 --
Index: SQL/postgres.update.sql
===================================================================
--- SQL/postgres.update.sql	(revision 3e48d2eee1d2af42aa777fd5e461fa570762732e)
+++ SQL/postgres.update.sql	(revision dcf780a6bd5065ffb0dcc76233b1e5f601e258d2)
@@ -25,7 +25,5 @@
 -- Updates from version 0.2-beta
 
-ALTER TABLE cache DROP CONSTRAINT cache_session_id_fkey;
-ALTER TABLE cache ADD FOREIGN KEY (session_id) REFERENCES session (sess_id) ON DELETE CASCADE ON UPDATE CASCADE;
+ALTER TABLE cache DROP session_id;
 
-CREATE INDEX cache_session_id_idx ON cache (session_id);
 CREATE INDEX session_changed_idx ON session (changed);
Index: SQL/sqlite.initial.sql
===================================================================
--- SQL/sqlite.initial.sql	(revision 3e48d2eee1d2af42aa777fd5e461fa570762732e)
+++ SQL/sqlite.initial.sql	(revision dcf780a6bd5065ffb0dcc76233b1e5f601e258d2)
@@ -12,5 +12,4 @@
   cache_id integer NOT NULL PRIMARY KEY,
   user_id integer NOT NULL default 0,
-  session_id varchar(40) default NULL,
   cache_key varchar(128) NOT NULL default '',
   created datetime NOT NULL default '0000-00-00 00:00:00',
Index: program/include/rcube_imap.php
===================================================================
--- program/include/rcube_imap.php	(revision 3e48d2eee1d2af42aa777fd5e461fa570762732e)
+++ program/include/rcube_imap.php	(revision dcf780a6bd5065ffb0dcc76233b1e5f601e258d2)
@@ -2147,9 +2147,8 @@
       $this->db->query(
         "UPDATE ".get_table_name('cache')."
-         SET    created=". $this->db->fromunixtime(time()).", data=?, session_id=?
+         SET    created=". $this->db->now().", data=?
          WHERE  user_id=?
          AND    cache_key=?",
         $data,
-	session_id(),
         $_SESSION['user_id'],
         $key);
@@ -2160,10 +2159,9 @@
       $this->db->query(
         "INSERT INTO ".get_table_name('cache')."
-         (created, user_id, cache_key, data, session_id)
-         VALUES (".$this->db->fromunixtime(time()).", ?, ?, ?, ?)",
+         (created, user_id, cache_key, data)
+         VALUES (".$this->db->now().", ?, ?, ?)",
         $_SESSION['user_id'],
         $key,
-        $data,
-	session_id());
+        $data);
       }
     }
@@ -2375,5 +2373,5 @@
         "INSERT INTO ".get_table_name('messages')."
          (user_id, del, cache_key, created, idx, uid, subject, ".$this->db->quoteIdentifier('from').", ".$this->db->quoteIdentifier('to').", cc, date, size, headers, structure)
-         VALUES (?, 0, ?, ".$this->db->fromunixtime(time()).", ?, ?, ?, ?, ?, ?, ".$this->db->fromunixtime($headers->timestamp).", ?, ?, ?)",
+         VALUES (?, 0, ?, ".$this->db->now().", ?, ?, ?, ?, ?, ?, ".$this->db->fromunixtime($headers->timestamp).", ?, ?, ?)",
         $_SESSION['user_id'],
         $key,
Index: program/include/session.inc
===================================================================
--- program/include/session.inc	(revision 3e48d2eee1d2af42aa777fd5e461fa570762732e)
+++ program/include/session.inc	(revision dcf780a6bd5065ffb0dcc76233b1e5f601e258d2)
@@ -112,10 +112,4 @@
   $DB->query("DELETE FROM " . get_table_name('session') . " WHERE sess_id=?", $key);
 
-  // delete session entries in cache table
-  // on databases wthout foreign keys
-  if ($rcmail->config->get('enable_caching') && $DB->db_provider != 'pgsql') {
-    $DB->query("DELETE FROM " . get_table_name('cache') . " WHERE session_id=?", $key);
-  }
-
   return true;
 }
@@ -132,32 +126,6 @@
   }
 
-  $now = $DB->fromunixtime(time() - $maxlifetime);
-
-  // delete session entries in cache table
-  if ($rcmail->config->get('enable_caching')) {
-
-    // on databases wthout foreign keys...
-    if($DB->db_provider != 'pgsql') {
-
-      // get all expired sessions
-      $sql_result = $DB->query(
-	"SELECT sess_id FROM " . get_table_name('session') . "
-    	    WHERE changed < " . $now);
-
-      $exp_sessions = array();
-      while ($sql_arr = $DB->fetch_assoc($sql_result)) {
-        $exp_sessions[] = $sql_arr['sess_id'];
-      }
-
-      if (sizeof($exp_sessions)) {
-        $exp_sessions = "'" . join("','", $exp_sessions) . "'";
-        // delete session cache records
-        $DB->query("DELETE FROM " . get_table_name('cache') . "
-            WHERE session_id IN (" . $exp_sessions . ")");
-      }
-    }
-    // also run message cache GC
+  if ($rcmail->config->get('enable_caching'))
     rcmail_message_cache_gc();
-  }
 
   // just delete all expired sessions