- Performance improvement: made 'sid' the primary key of the sessions table.

  That should improve performance of session handling as well improve
  performance of the "Who's online"-block.  Drupal.org's sessions table
  contains appr. 40.000 sessions on a slow day and rendering the "Who's
  online"-block became a performance bottleneck.

  This change has yet to be tested on a busy site so things might go wrong.

2 files changed, 13 insertions, 2 deletions

diff --git a/database/database.mysql b/database/database.mysql
index f8be88bbc..7e8478852 100644
--- a/database/database.mysql
+++ b/database/database.mysql
@@ -567,7 +567,7 @@ CREATE TABLE sessions (
   timestamp int(11) NOT NULL default '0',
   session longtext,
   KEY uid (uid),
-  KEY sid (sid),
+  PRIMARY KEY sid (sid),
   KEY timestamp (timestamp)
 ) TYPE=MyISAM;
 
diff --git a/database/updates.inc b/database/updates.inc
index e135ae431..148119757 100644
--- a/database/updates.inc
+++ b/database/updates.inc
@@ -86,7 +86,8 @@ $sql_updates = array(
   "2004-09-17" => "update_107",
   "2004-10-16" => "update_108",
   "2004-10-18" => "update_109",
-  "2004-10-31: first update since Drupal 4.5.0 release" => "update_110"
+  "2004-10-31: first update since Drupal 4.5.0 release" => "update_110",
+  "2004-11-07" => "update_111"
 );
 
 function update_32() {
@@ -1966,6 +1967,16 @@ function update_110() {
   return $ret;
 }
 
+function update_111() {
+  $ret = array();
+
+  if ($GLOBALS['db_type'] == 'mysql') {
+    $ret[] = update_sql('ALTER TABLE {sessions} ADD PRIMARY KEY sid (sid)');
+  }
+
+  return $ret;
+}
+
 function update_sql($sql) {
   $edit = $_POST["edit"];
   $result = db_query($sql);