Neil, Ooops, I had read your post a bit fast - I have since found the queries and what did I find in them? Cough, cough. SF Neil Kodner wrote: > Now that things are slow and unresponsive, I've been asked to join the > fray. > > Little bit of background: > DW-type environment > 4 CPU Solaris 10 > optimizer_index_caching 90 > optimizer_index_cost_adj 50 > > I didn't set the optimizer parameters, I'm of the 'leave them alone' > school. > > Once our environment was upgraded from 9.2.0.4 to 10.2.0.4, everything > seemed ok except for UPDATE statements that contain correlated select > statements. Across the board, we received poor performance compared > to running them in 9.2. > > Another disclaimer-I didn't write this query-but it ran in 3 minutes > in 9i. > > Altering the session and setting optimizer_index_cost_adj=100 and > optimizer_index_caching=0 didn't make a difference. > > A common denominator is that the session-altered plans have a SORT > UNIQUE step and the default 10g plans do not. > > Rather than clutter up the post with the queries and 2 versions of > explain plans, I wrote everything to a file on my site. > http://www.neilkodner.com/plan_differences.txt > > Would love to hear help/feedback/whatever - I'm struggling with this > and altering the session each time is unacceptable. -- //www.freelists.org/webpage/oracle-l