The problem seems to be specific to 11g, both R1 and R2, regardless platform (you can find this string "Can not perform hang analysis dump..." in 11g oracle binary). The bug is filed against 11gR1 on Linux but with comment "Affects Platform Generic": https://supporthtml.oracle.com/ep/faces/secure/km/BugDisplay.jspx?id=9339579&bugProductSource=Oracle Since session and process state objects can be created in 10g, I guess the -prelim option of sqlplus in 10g is not as lightweight as in 11g. Yong Huang -- //www.freelists.org/webpage/oracle-l