your query have a greater than 8 in it.  I know that each xml document is allocated 1/8th of the memory.  but does that mean only 8 can exist at a time.  Is the 1/8th allocation of total memory, so it is static, or is it 1/8th of available.
Also, the database I am having problems with is high volume (thousands of concurrent users)  with hundreds or even thousands of transactions a minute.