Optimize subquery that searches xml
2 suggestions:


do you really need a LIKE, can't you use an equality?
can't you try to first filter the XML and then (but still in the same query) going up with the needed joins to retrieve what you need ?


Also your performances obviously depend on the size of various tables and on the available indexes. Your RDBM should be able to let you know which indexes it will use for your above query and based on that you may find you are missing some. Filtering on dates, xml, and LIKE patterns has a cost.