Changing session->data to medium text. Bug 5406.

(http://moodle.org/bugs/bug.php?op=show&bugid=5406)

Merged from MOODLE_16_STABLE

lib/db/migrate2utf8.xml

@@ -289,7 +289,7 @@
       <FIELDS>
         <FIELD name="sesskey" method="NO_CONV" type="varchar" length="32" dropprimary="true" addprimary="(sesskey(32))"/>
         <FIELD name="expireref" method="NO_CONV" type="varchar" length="64" />
-        <FIELD name="data" method="NO_CONV" type="text" length="0" />
+        <FIELD name="data" method="NO_CONV" type="mediumtext" length="0" />
       </FIELDS>
     </TABLE>
     <TABLE name="timezone">

lib/db/mysql.php

@@ -1945,6 +1945,10 @@ function main_upgrade($oldversion=0) {
     if ($oldversion < 2006050500) {
         table_column('log', 'action', 'action', 'varchar', '40', '', '', 'not null');
     }
+
+    if ($oldversion < 2006050501) {
+        table_column('sessions', 'data', 'data', 'mediumtext', '', '', '', 'not null');
+    }
     
     return $result;
 }

lib/db/mysql.sql

@@ -539,7 +539,7 @@ CREATE TABLE `prefix_sessions` (
   `sesskey` char(32) NOT null default '',
   `expiry` int(11) unsigned NOT null default '0',
   `expireref` varchar(64) default '',
-  `data` text NOT null default '',
+  `data` mediumtext NOT null default '',
   PRIMARY KEY (`sesskey`), 
   KEY (`expiry`) 
 ) TYPE=MyISAM COMMENT='Optional database session storage, not used by default';