diff --git a/core/dbunionsearch.class.php b/core/dbunionsearch.class.php
index 07f2b8cee..d2c07fb7d 100644
--- a/core/dbunionsearch.class.php
+++ b/core/dbunionsearch.class.php
@@ -496,19 +496,30 @@ class DBUnionSearch extends DBSearch
 				$aSearchSelectedClasses[$sSearchAlias] = $this->aSelectedClasses[$sAlias];
 			}
 
-			if (is_null($aAttToLoad))
+			if ($bGetCount)
 			{
-				$aQueryAttToLoad = null;
+				// Select only ids for the count to allow optimization of joins
+				foreach($aSearchAliases as $sSearchAlias)
+				{
+					$aQueryAttToLoad[$sSearchAlias] = array();
+				}
 			}
 			else
 			{
-					// (Eventually) Transform the aliases
-				$aQueryAttToLoad = array();
-				foreach ($aAttToLoad as $sAlias => $aAttributes)
+				if (is_null($aAttToLoad))
 				{
-					$iColumn = array_search($sAlias, $aAliases);
-					$sQueryAlias = ($iColumn === false) ? $sAlias : $aSearchAliases[$iColumn];
-					$aQueryAttToLoad[$sQueryAlias] = $aAttributes;
+					$aQueryAttToLoad = null;
+				}
+				else
+				{
+					// (Eventually) Transform the aliases
+					$aQueryAttToLoad = array();
+					foreach($aAttToLoad as $sAlias => $aAttributes)
+					{
+						$iColumn = array_search($sAlias, $aAliases);
+						$sQueryAlias = ($iColumn === false) ? $sAlias : $aSearchAliases[$iColumn];
+						$aQueryAttToLoad[$sQueryAlias] = $aAttributes;
+					}
 				}
 			}
 
diff --git a/sources/renderer/bootstrap/fieldrenderer/bsselectobjectfieldrenderer.class.inc.php b/sources/renderer/bootstrap/fieldrenderer/bsselectobjectfieldrenderer.class.inc.php
index c2d05a828..e770aaede 100644
--- a/sources/renderer/bootstrap/fieldrenderer/bsselectobjectfieldrenderer.class.inc.php
+++ b/sources/renderer/bootstrap/fieldrenderer/bsselectobjectfieldrenderer.class.inc.php
@@ -103,6 +103,7 @@ class BsSelectObjectFieldRenderer extends FieldRenderer
 					$oOutput->AddHtml('<option value="">')->AddHtml(Dict::S('UI:SelectOne'), false)->AddHtml('</option>');
 					// - Retrieving choices
 					$oChoicesSet = new DBObjectSet($oSearch);
+					$oChoicesSet->OptimizeColumnLoad(array($oSearch->GetClassAlias() => array('friendlyname')));
 					while ($oChoice = $oChoicesSet->Fetch())
 					{
 						// Note : The test is a double equal on purpose as the type of the value received from the XHR is not always the same as the type of the allowed values. (eg : string vs int)