Is XML Variant Type's Size Is Limited? Or Anything Wrong?

Can anyone help on this?
In SQL 2005, I use a variant with XML type; it seems that its size is limited here. If I assign a big data to it, it appears not assigned at all. Here is the example:



Code Snippet
declare @xml xml
--cross two table to get many records returned, if nothing is abnormal, just cross more tables here
select * from master.sys.objects a, master.sys.objects b for xml RAW, ELEMENTS
set @xml=( select * from master.sys.objects a, master.sys.objects b for xml RAW, ELEMENTS )
select @xml
--no results here for var @xml

--use single table to get fewer records returned.
select * from master.sys.objects for xml RAW, ELEMENTS
set @xml=( select * from master.sys.objects for xml RAW, ELEMENTS )
select @xml
--results as normal.


Note:here I don't want to test SQL server, I just use XML type variant as oupput for a sproc, and come across the issue here.



Any reply will be appreciated!