What does maxquerylen in v$undostat really mean?

I am using Oracle9i on HP UNIX 11i. When I do

select max(maxquerylen) from v$undostat

I get a number 13748 which is in seconds which is between 3-4 hours.

When I look in v$sqlarea for the maximum elapsed_time taken by any query it is only:
798220317

which I assume is in micro seconds, i.e., 798 seconds.

I am puzzled what exactly does maxquerylen mean, does it mean time in seconds taken by a query (that does not seem to be the case) or is it maximum time taken by a transaction.

Thanks,

Prem Received on Fri Dec 10 2004 - 23:37:11 CST