Need guidance - forum topic by HateOra

Hi,
 
I have a bteq job which is running MERGE on fact table.
there is a JI bult on my fatc table.
 
while executing the MERGE suddenly the query started failing with spool space error, even thogh there is no load on server.
 
also when i monitored the performance of the query in Viewpoint.. i could see that it was running with 99.6 % CPU skew and 99.6% IO skew..
 
Could you please advice me how to do investigation on this?
 
any canary query that can help me , please provide.