Rich, > Are there LOB(s) in the table being updated? No LOBs in the table (and thus none being updated). > I think CURRENT_OBJ# is set equal to -1 before being updated by the process > with the > actual object number (some of the sampling just caught it before it was > populated). Hmm, it's nearly half of the waits. Could it really be that? > Are the rows being updated "clean"? > (thinking it might be deferred block cleanout and/or transaction rollbacks?) You might be onto something. The AWR report (that led me to investigate the UPDATE statement) shows the following: Statistic Total per Second per Trans -------------------------------------------------------------------------------------------- cleanout - number of ktugct calls 189,612 52.55 6.07 cleanouts and rollbacks - consistent read gets 62,875 17.43 2.01 cleanouts only - consistent read gets 40,159 11.13 1.29 transaction rollbacks 37 0.01 0.00 transaction tables consistent read rollbacks 1 0.00 0.00 transaction tables consistent reads - undo records applied 1 0.00 0.00 user commits 28,799 7.98 0.92 user rollbacks 2,437 0.68 0.08 The report covers 60 minutes > Can you trace the update in question? Unfortunately not. Regards Thomas -- //www.freelists.org/webpage/oracle-l