Jeff,
I did check the v$sort_usage , but I couldnt see any user except SYSTEM user doing sorts now.

And I also queried v$sort_segment, here the values i found

Total extents : 499
Total blocks :255488
Used extents : 58
used blocks : 29696
extent hits : 8689
max sort blocks : 46592

And to remember you again , 99% of my sorts are on memeory ... May be u may have some picture now with the above details.

I think the TEMP tablespace is having enough space left over , but still i am getting the error , not on every day but atleast once in a week.

I would like to arrest this problem.. Is there anyway to check to see the biggest sort in the past ???

Still I am not clear , how to solve this problem???

PS: I am not having any Global Temporary tables and just to rememeber this is a locally managed tablespace with nologging option and unform , 4MB

thanks for your help,
Madhu