I have three temporaray tablespaces with 10 GB each .
Recently , When we run some query we are getting unable to
extent temp segment (ORA 1652 ) . We were running same query for last three months without any problems.

These queries used to take 20 minutes, and they are now taking 90 to 180 minutes to complete.

However, what I don't understand is how a query on 300Mb of data, which is summarizing statistcs on 6000-10000 distinct groups and producing a 20 Mb summary can use over 10GB of temporary table space.

Could anyone have any idea ?