sql插入语句有时无法正常工作

$query = mysql_query(\"QUERY\", $db_connection) or trigger_error(mysql_error());

function dbInsertQuery($query, $conn) {
     $logFile = \"/path/to/file.txt\";
     $isProd  = FALSE;

     // run your security checks on the query here

     $mysql_query($query, $db_connection) or trigger_error(mysql_error());

     if (!$isProd && is_writable($logFile)) {
       if (!handle = fopen($logFile, \'a\')) {
         echo \"cannot open dbInsertQuery\'s log file: \" . $logFile;
         exit;
       } 

       $logLine = date(DATE_RFC822) . \" - \" . $query;

       if (fwrite($handle, $logLine) === FALSE) {
         echo \"cannot write to dbInsertQuery\'s log file: \" . $logFile;
         exit;
       }

       fclose($handle);
     }

   }

$isProd

TRUE