[dev] Horde_Ldap performance problem + patch

[Xavier Montagutelli]

Hi list,

I have identified a serious performance problem in the Horde_Ldap module.

When doing a very simple search on a directory with around 50.000 entries, 
getting the results with the "shiftEntry" methods takes a *very* long time, 
compared to using the native PHP functions.

This renders the "listUsers" method in the LDAP auth handler for Horde 
useless.

Some numbers :

1. Using PHP native LDAP functions
Number of entries                : 44588
Search time                      : 2 seconds
Building list from search result : 1 seconds

2. Using Horde_Ldap object
Number of entries                : 44588
Search time                      : 2 seconds
Building list from search result : 112 seconds


With Xdebug, I have identified the bottleneck. Each call to "shiftEntry" calls 
"count", and this one calls "ldap_count_entries". I suppose this function goes 
through all the remaining results to give the count, so calling it 
inefficient.

With the following patch, it turns to be *much* quicker (~ 6 seconds to build 
the result list).

--- Horde/Ldap/Search.php.orig  2011-08-23 12:41:42.000000000 +0200
+++ Horde/Ldap/Search.php       2011-08-23 12:45:15.000000000 +0200
@@ -145,10 +145,6 @@
      */
     public function shiftEntry()
     {
-        if (!$this->count()) {
-            return false;
-        }
-
         if (is_null($this->_entry)) {
             $this->_entry = @ldap_first_entry($this->_link, $this->_search);
             $entry = Horde_Ldap_Entry::createConnected($this->_ldap, $this-
>_entry);


From my point of view, the call to "count" is useless, as ldap_first_entry or 
ldap_next_entry will return false at the end. Or do I miss something ?


(BTW, the Net_LDAP2 code suffers from the same problem ...)


My code to compare performance is :


// Initialisation code 
[...]
$filter = '(objectclass=inetOrgPerson)';
$attr = array('uid');

// Methode 1. Using LDAP native functions
$t0 = time();
$ldap = ldap_connect($h);
ldap_bind($ldap, $user, $pass);
$search = ldap_search ($ldap,
                $basedn,
                $filter,
                $attr);
$t1 = time();

$userlist = array();
$entry = ldap_first_entry($ldap, $search);
while ($entry) {
   $values = ldap_get_values ($ldap, $entry, 'uid');
   $userlist[] = $values[0];
   $entry = ldap_next_entry($ldap, $entry);
}
ldap_free_result($search);
ldap_close($ldap);
$t2 = time();

echo "1. Using PHP native LDAP functions\n";
echo "Number of entries                : " . count($userlist) . "\n";
echo "Search time                      : " . ($t1-$t0) . " seconds\n";
echo "Building list from search result : " . ($t2-$t1) . " seconds\n";

// Methode 2. Using Horde_Ldap object
$t0 = time();
$ldap = new Horde_Ldap(array (
                'hostspec' => $h,
                'binddn' => $user,
                'bindpw' => $pass));
$search = $ldap->search(
    $basedn,
    $filter,
    array ('attributes' => $attr)
);
$t1 = time();

$userlist = array();
while ($entry = $search->shiftEntry()) {
    $userlist[] = $entry->getValue('uid', 'single');
}
$t2 = time();

echo "2. Using Horde_Ldap object\n";
echo 'Number of entries                : ' . count($userlist) . "\n";
echo 'Search time                      : ' . ($t1-$t0) . " seconds\n";
echo 'Building list from search result : ' . ($t2-$t1) . " seconds\n";



-- 
Xavier Montagutelli                      Tel : +33 (0)5 55 45 77 20
Service Commun Informatique              Fax : +33 (0)5 55 45 75 95
Universite de Limoges
123, avenue Albert Thomas
87060 Limoges cedex