After some time of serching I always got this error:
Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 8388608 bytes) in /var/www/forum/includes/search/fulltext_native.php on line 1180
My memory limit in php.ini is 512mb... I use Percona 5.5 mysql server and all the tables are in innodb.
Any ideas how I can fix it?