Index: extension/ezsi/classes/ezsiblockfunction.php
===================================================================
--- extension/ezsi/classes/ezsiblockfunction.php	(revision 62)
+++ extension/ezsi/classes/ezsiblockfunction.php	(working copy)
@@ -208,6 +208,14 @@
 
                         $htmlContents = $this->processChildren( $tpl, $functionChildren, $rootNamespace, $currentNamespace );
 
+                        // A different process might have just generated
+                        // the file after processing a very heavy template
+                        // this avoid using a mutex
+                        if( $this->fileExists() )
+                        {
+                            break;
+                        }
+
                         $db = eZDB::instance();
                         $db->begin();